This document is scheduled to be published in the
Federal Register on 08/12/2016 and available online at
http://federalregister.gov/a/2016-17954, and on FDsys.gov

Billing Code 4410-09-P
DEPARTMENT OF JUSTICE
Drug Enforcement Administration
21 CFR Chapter II
[Docket No. DEA-426]
Denial of Petition to Initiate Proceedings to Reschedule Marijuana

AGENCY: Drug Enforcement Administration, Department of Justice.
ACTION: Denial of petitition to initiate proceedings to reschedule marijuana..
SUMMARY: By letter dated July 19, 2016 the
Drug Enforcement Administration (DEA) denied a petition to initiate rulemaking
proceedings to reschedule marijuana. Because the DEA believes that this matter is of
particular interest to members of the public, the agency is publishing below the letter sent
to the petitioner which denied the petition, along with the supporting documentation that
was attached to the letter.
DATES: [Insert date of publication in the Federal Register].
FOR FURTHER INFORMATION CONTACT: Michael J. Lewis, Office of Diversion
Control, Drug Enforcement Administration; Mailing Address: 8701 Morrissette Drive,
Springfield, Virginia 22152; Telephone: (202) 598–6812
SUPPLEMENTARY INFORMATION:
July 19, 2016
Dear Ms. Raimondo and Mr. Inslee:
On November 30, 2011, your predecessors, The Honorable Lincoln D. Chafee and
The Honorable Christine O. Gregoire, petitioned the Drug Enforcement Administration
(DEA) to initiate rulemaking proceedings under the rescheduling provisions of the
Controlled Substances Act (CSA). Specifically, your predecessors petitioned the DEA to

1

 have marijuana and “related items” removed from Schedule I of the CSA and
rescheduled as medical cannabis in Schedule II.
Your predecessors requested that the DEA remove marijuana and related items from
Schedule I based on their assertion that:
1) Cannabis has accepted medical use in the United States;
2) Cannabis is safe for use under medical supervision;
3) Cannabis for medical purposes has a relatively low potential for abuse,
especially in comparison with other Schedule II drugs.
In accordance with the CSA rescheduling provisions, after gathering the necessary
data, the DEA requested a scientific and medical evaluation and scheduling
recommendation from the Department of Health and Human Services (HHS). The HHS
concluded that marijuana has a high potential for abuse, has no accepted medical use in
the United States, and lacks an acceptable level of safety for use even under medical
supervision. Therefore, the HHS recommended that marijuana remain in Schedule I.
The scientific and medical evaluation and scheduling recommendation that the HHS
submitted to the DEA is enclosed with this letter.
Based on the HHS evaluation and all other relevant data, the DEA has concluded that
there is no substantial evidence that marijuana should be removed from Schedule I. A
document prepared by the DEA addressing these materials in detail also is enclosed. In
short, marijuana continues to meet the criteria for Schedule I control under the CSA
because:
1) Marijuana has a high potential for abuse. The HHS evaluation and the

additional data gathered by the DEA show that marijuana has a high potential
for abuse.
2) Marijuana has no currently accepted medical use in treatment in the United
States. Based on the established five-part test for making such determination,
marijuana has no “currently accepted medical use” because: As detailed in the
HHS evaluation, the drug’s chemistry is not known and reproducible; there
are no adequate safety studies; there are no adequate and well-controlled
studies proving efficacy; the drug is not accepted by qualified experts; and the
scientific evidence is not widely available.
3) Marijuana lacks accepted safety for use under medical supervision. At
present, there are no marijuana products approved by the U.S. Food and Drug
Administration (FDA), nor is marijuana under a New Drug Application
(NDA) evaluation at the FDA for any indication. The HHS evaluation states
that marijuana does not have a currently accepted medical use in treatment in
the United States or a currently accepted medical use with severe restrictions.
At this time, the known risks of marijuana use have not been shown to be
outweighed by specific benefits in well-controlled clinical trials that
scientifically evaluate safety and efficacy.
2

 The statutory mandate of Title 21 United States Code, Section 812(b) (21 U.S.C. §
812(b)) is dispositive. Congress established only one schedule, Schedule I, for drugs of
abuse with “no currently accepted medical use in treatment in the United States” and
“lack of accepted safety for use . . . under medical supervision.” 21 U.S.C. § 812(b).
Although the HHS evaluation and all other relevant data lead to the conclusion that
marijuana must remain in schedule I, it should also be noted that, in view of United States
obligations under international drug control treaties, marijuana cannot be placed in a
schedule less restrictive than schedule II. This is explained in detail in accompanying
document titled “Preliminary Note Regarding Treaty Considerations.”
Accordingly, and as set forth in detail in the accompanying HHS and DEA
documents, there is no statutory basis under the CSA for the DEA to grant your
predecessors’ petition to initiate rulemaking proceedings to reschedule marijuana. The
petition is, therefore, hereby denied.

Sincerely,
Chuck Rosenberg
Acting Administrator

Attachments:
Preliminary Note Regarding Treaty Considerations
Cover Letter from HHS to DEA Summarizing the Scientific and Medical Evaluation and
Scheduling Recommendation for Marijuana.
U.S. Department of Health and Human Services (HHS) – Basis for the Recommendation
for Maintaining Marijuana in Schedule I of the Controlled Substances Act
U.S. Department of Justice - Drug Enforcement Administration (DEA), Schedule of
Controlled Substances: Maintaining Marijuana in Schedule I of the Controlled
Substances Act, Background, Data, and Analysis: Eight Factors Determinative of Control
and Findings Pursuant to 21 U.S.C. 812(b)
Date: 07/19/2016

Chuck Rosenberg,
Acting Administrator
3

 Preliminary Note Regarding Treaty Considerations
As the Controlled Substances Act (CSA) recognizes, the United States is a party
to the Single Convention on Narcotic Drugs, 1961 (referred to here as the Single
Convention or the treaty). 21 U.S.C. 801(7). Parties to the Single Convention are
obligated to maintain various control provisions related to the drugs that are covered by
the treaty. Many of the provisions of the CSA were enacted by Congress for the specific
purpose of ensuring U.S. compliance with the treaty. Among these is a scheduling
provision, 21 U.S.C. 811(d)(1). Section 811(d)(1) provides that, where a drug is subject
to control under the Single Convention, the DEA Administrator (by delegation from the
Attorney General) must “issue an order controlling such drug under the schedule he
deems most appropriate to carry out such [treaty] obligations, without regard to the
findings required by [21 U.S.C. 811(a) or 812(b)] and without regard to the procedures
prescribed by [21 U.S.C. 811(a) and (b)].”
Marijuana is a drug listed in the Single Convention. The Single Convention uses
the term “cannabis” to refer to marijuana.1 Thus, the DEA Administrator is obligated
under section 811(d) to control marijuana in the schedule that he deems most appropriate
to carry out the U.S. obligations under the Single Convention. It has been established in
prior marijuana rescheduling proceedings that placement of marijuana in either schedule I
or schedule II of the CSA is “necessary as well as sufficient to satisfy our international
obligations” under the Single Convention. NORML v. DEA, 559 F.2d 735, 751 (D.C. Cir.
1977). As the United States Court of Appeals for the D.C. Circuit has stated, “several
requirements imposed by the Single Convention would not be met if cannabis and
cannabis resin were placed in CSA schedule III, IV, or V.”2 Id. Therefore, in accordance
with section 811(d)(1), DEA must place marijuana in either schedule I or schedule II.
Because schedules I and II are the only possible schedules in which marijuana
may be placed, for purposes of evaluating this scheduling petition, it is essential to
understand the differences between the criteria for placement of a substance in schedule I
and those for placement in schedule II. These criteria are set forth in 21 U.S.C. 812(b)(1)
and (b)(2), respectively. As indicated therein, substances in both schedule I and schedule
1

Under the Single Convention, “cannabis plant’ means any plant of the genus Cannabis.” Article 1(c).
The Single Convention defines “cannabis” to include “the flowering or fruiting tops of the cannabis plant
(excluding the seeds and leaves when not accompanied by the tops) from which the resin has not been
extracted, by whatever name they may be designated.” Article 1(b). This definition of “cannabis” under
the Single Convention is slightly less inclusive than the CSA definition of "marihuana," which includes all
parts of the cannabis plant except for the mature stalks, sterilized seeds, oil from the seeds, and certain
derivatives thereof. See 21 U.S.C. § 802(16). Cannabis and cannabis resin are included in the list of drugs
in Schedule I and Schedule IV of the Single Convention. In contrast to the CSA, the drugs listed in
Schedule IV of the Single Convention are also listed in Schedule I of the Single Convention and are subject
to the same controls as Schedule I drugs as well as additional controls. Article 2, par. 5
2

The Court further stated: “For example, [article 31 paragraph 4 of the Single Convention] requires import
and export permits that would not be obtained if the substances were placed in CSA schedules III through
V. In addition, the quota and [recordkeeping] requirements of Articles 19 through 21 of the Single
Convention would be satisfied only by placing the substances in CSA schedule I or II.” Id. n. 71 (internal
citations omitted).

4

 II share the characteristic of “a high potential for abuse.” Where the distinction lies is
that schedule I drugs have “no currently accepted medical use in treatment in the United
States” and “a lack of accepted safety for use of the drug . . . under medical
supervision,” while schedule II drugs do have “a currently accepted medical use in
treatment in the United States.” 3
Accordingly, in view of section 811(d)(1), this scheduling petition turns on
whether marijuana has a currently accepted medical use in treatment in the United States.
If it does not, DEA must, pursuant to section 811(d), deny the petition and keep
marijuana in schedule I.
As indicated, where section 811(d)(1) applies to a drug that is the subject of a
rescheduling petition, the DEA Administrator must issue an order controlling the drug
under the schedule he deems most appropriate to carry out United States obligations
under the Single Convention, without regard to the findings required by sections 811(a)
or 812(b) and without regard to the procedures prescribed by sections 811(a) and (b).
Thus, since the only determinative issue in evaluating the present scheduling petition is
whether marijuana has a currently accepted medical use in treatment in the United States,
DEA need not consider the findings of sections 811(a) or 812(b) that have no bearing on
that determination, and DEA likewise need not follow the procedures prescribed by
sections 811(a) and (b) with respect to such irrelevant findings. Specifically, DEA need
not evaluate the relative abuse potential of marijuana or the relative extent to which abuse
of marijuana may lead to physical or psychological dependence.
As explained below, the medical and scientific evaluation and scheduling
recommendation issued by the Secretary of Health and Human Services concludes that
marijuana has no currently accepted medical use in treatment in the United States, and
the DEA Administrator likewise so concludes. For the reasons just indicated, no further
analysis beyond this consideration is required. Nonetheless, because of the widespread
public interest in understanding all the facts relating to the harms associated with
marijuana, DEA is publishing here the entire medical and scientific analysis and
scheduling evaluation issued by the Secretary, as well as DEA's additional analysis.

3

As DEA has stated in evaluating prior marijuana rescheduling petitions, “Congress established only one
schedule, schedule I, for drugs of abuse with 'no currently accepted medical use in treatment in the United
States' and 'lack of accepted safety for use . . . under medical supervision.' 21 USC 812(b).” 76 FR 40552
(2011); 66 FR 20038 (2001).

5

 Department of Health and Human Services,
Office of the Secretary Assistant Secretary for Health, Office of Public Health and
Science
Washington D.C. 20201.
June 25, 2015.
The Honorable Chuck Rosenberg
Acting Administrator, Drug Enforcement Administration, U.S. Department of Justice,
8701 Morrissette Drive, Springfield, VA 22152
Dear Mr. Rosenberg:
Pursuant to the Controlled Substances Act (CSA, 21 U.S.C § 811(b), (c), and (f)), the
Department of Health and Human Services (HHS) is recommending that marijuana
continue to be maintained in Schedule I of the CSA.
The Food and Drug Administration (FDA) has considered the abuse potential and
dependence-producing characteristics of marijuana.
Marijuana meets the three criteria for placing a substance in Schedule I of the CSA under
21 U.S.C 812(b)(1). As discussed in the enclosed analyses, marijuana has a high
potential for abuse, no currently accepted medical use in treatment in the United States,
and a lack of accepted safety for use under medical supervision. Accordingly, HHS
recommends that marijuana be maintained in Schedule I of the CSA. Enclosed are two
documents prepared by FDA’s Controlled Substance Staff (in response to petitions filed
in 2009 by Mr. Bryan Krumm and in 2011 by Governors Lincoln D. Chafee and
Christine O. Gregoire) that form the basis for the recommendation. Pursuant to the
requests in the petitions, FDA broadly evaluated marijuana, and did not focus its
evaluation on particular strains of marijuana or components or derivatives of marijuana.
FDA’s Center for Drug Evaluation and Research’s current review of the available
evidence and the published clinical studies on marijuana demonstrated that since our
2006 scientific and medical evaluation and scheduling recommendation responding to
a previous DEA petition, research with marijuana has progressed. However, the
available evidence is not sufficient to determine that marijuana has an accepted medical
use. Therefore, more research is needed into marijuana’s effects, including potential
medical uses for marijuana and its derivatives. Based on the current review, we
identified several methodological challenges in the marijuana studies published in the
literature. We recommend they be addressed in future clinical studies with marijuana to
ensure that valid scientific data are generated in studies evaluating marijuana’s safety and
efficacy for therapeutic use. For example, we recommend that studies need to focus on
consistent administration and reproducible dosing of marijuana, potentially through the
use of administration methods other than smoking. A summary of our review of the
published literature on the clinical uses of marijuana, including recommendations for
future studies, is attached to this document.
6

 FDA and the National Institutes of Health’s National Institute on Drug Abuse (NIDA)
also believe that work continues to be needed to ensure support by the federal
government for the efficient conduct of clinical research using marijuana. Concerns have
been raised about whether the existing federal regulatory system is flexible enough to
respond to increased interest in research into the potential therapeutic uses of marijuana
and marijuana-derived drugs. HHS welcomes an opportunity to continue to explore these
concerns with DEA.
Should you have any questions regarding theses recommendations, please contact
Corinne P. Moody, Science Policy Analyst, Controlled Substances Staff, Center for Drug
Evaluation and Research, FDA, at (301) 796-3152.
Sincerely yours,
Karen B. DeSalvo, MD, MPH, MSc
Acting Assistant Secretary for Health
Enclosure:
Basis for the Recommendation for Maintaining Marijuana in Schedule I of the Controlled
Substances Act

BASIS FOR THE RECOMMENDATION FOR
MAINTAINING MARIJUANA IN SCHEDULE I
OF THE CONTROLLED SUBSTANCES ACT

On November 30, 2011, Governors Lincoln D. Chafee of Rhode Island and Christine O.
Gregoire of Washington submitted a petition to the Drug Enforcement Administration
(DEA) requesting that proceeding be initiated to repeal the rules and regulations that
place marijuana4 in Schedule I of the Controlled Substances Act (CSA). The petition
contends that cannabis has an accepted medical use in the United States, is safe for use
under medical supervision, and has a relatively low abuse potential compared to other
Schedule II drugs. The petition requests that marijuana and “related items” be
rescheduled in Schedule II of the CSA. In June 2013, the DEA Administrator requested
that the U.S. Department of Health and Human Services (HHS) provide a scientific and
medical evaluation of the available information and a scheduling recommendation for
marijuana, in accordance with the provisions of 21 U.S.C. 811(b).

4

Note that “marihuana” is the spelling originally used in the Controlled Substances Act (CSA). This
document uses the spelling that is more common in current usage, “marijuana.”

7

 In accordance with 21 U.S.C. 811(b), DEA has gathered information related to the
control of marijuana (Cannabis sativa)5 under the CSA. Pursuant to 21 U.S.C. 811(b),
the Secretary of HHS is required to consider in a scientific and medical evaluation eight
factors determinative of control under the CSA. Following consideration of the eight
factors, if it is appropriate, the Secretary must make three findings to recommend
scheduling a substance in the CSA. The findings relate to a substance's abuse potential,
legitimate medical use, and safety or dependence liability.
Administrative responsibilities for evaluating a substance for control under the CSA are
performed by the Food and Drug Administration (FDA), with the concurrence of the
National Institute on Drug Abuse (NIDA), as described in the Memorandum of
Understanding (MOU) of March 8, 1985 (50 FR 9518-20).
In this document, FDA recommends the continued control of marijuana in Schedule I of
the CSA. Pursuant to 21 U.S.C. 811(c), the eight factors pertaining to the scheduling of
marijuana are considered below.
1. ITS ACTUAL OR RELATIVE POTENTIAL FOR ABUSE
Under the first factor the Secretary must consider marijuana's actual or relative
potential for abuse. The CSA does not define the term “abuse.” However, the CSA’s
legislative history suggests the following in determining whether a particular drug or
substance has a potential for abuse6:
a. There is evidence that individuals are taking the drug or drugs containing such a
substance in amounts sufficient to create a hazard to their health or to the safety of
other individuals or to the community.
b. There is a significant diversion of the drug or drugs containing such a substance
from legitimate drug channels.
c. Individuals are taking the drug or drugs containing such a substance on their own
initiative rather than on the basis of medical advice from a practitioner licensed by
law to administer such drugs in the course of his professional practice.
5

The CSA defines marijuana as the following:
All parts of the plant Cannabis Sativa L., whether growing or not; the seeds thereof; the resin
extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture,
or preparation of such plant, its seeds or resin. Such term does not include the mature stalks of
such plant, fiber produced from such stalks, oil or cake made from the seeds of such plant, any
other compound, manufacture, salt, derivative, mixture, or preparation of such mature stalks
(except the resin extracted therefrom), fiber, oil, or cake, or the sterilized seed of such plant which
is incapable of germination (21 U.S.C. 802(16)).

6

Comprehensive Drug Abuse Prevention and Control Act of 1970, H.R. Rep. No. 91-1444, 91st Cong.,
Sess. 1 (1970) reprinted in U.S.C.C.A.N. 4566, 4603.

8

 d. The drug or drugs containing such a substance are new drugs so related in their
action to a drug or drugs already listed as having a potential for abuse to make it
likely that the drug will have the same potentiality for abuse as such drugs, thus
making it reasonable to assume that there may be significant diversions from
legitimate channels, significant use contrary to or without medical advice, or that
it has a substantial capability of creating hazards to the health of the user or to the
safety of the community.

In the development of this scientific and medical evaluation for the purpose of
scheduling, the Secretary analyzed considerable data related to the substance’s abuse
potential. The data include a discussion of the prevalence and frequency of use, the
amount of the substance available for illicit use, the ease of obtaining or
manufacturing the substance, the reputation or status of the substance “on the street,”
and evidence relevant to at-risk populations. Importantly, the petitioners define
marijuana as including all Cannabis cultivated strains. Different marijuana samples
derived from various cultivated strains may have very different chemical constituents,
thus the analysis is based on what is known about the range of these constituents
across all cultivated strains.
Determining the abuse potential of a substance is complex with many dimensions, and
no single test or assessment provides a complete characterization. Thus, no single
measure of abuse potential is ideal. Scientifically, a comprehensive evaluation of the
relative abuse potential of a substance can include consideration of the following
elements: receptor binding affinity, preclinical pharmacology, reinforcing effects,
discriminative stimulus effects, dependence producing potential, pharmacokinetics,
route of administration, toxicity, data on actual abuse, clinical abuse potential studies,
and public health risks. Importantly, abuse can exist independently from tolerance or
physical dependence because individuals may abuse drugs in doses or patterns that do
not induce these phenomena. Additionally evidence of clandestine population and
illicit trafficking of a substance can shed light on both the demand for a substance as
well as the ease of obtaining a substance. Animal and human laboratory data and
epidemiological data are all used in determining a substance’s abuse potential.
Moreover, epidemiological data can indicate actual abuse.
The petitioners compare the effects of marijuana to currently controlled Schedule II
substances and make repeated claims about their comparative effects. Comparisons
between marijuana and the diverse array of Schedule II substances is difficult, because
of the pharmacologically dissimilar actions of substances of Schedule II of the CSA.
For example, Schedule II substances include stimulant-like drugs (e.g., cocaine,
methylphenidate, and amphetamine), opioids (e.g., oxycodone, fentanyl), sedatives
(e.g., pentobarbital, amobarbital), dissociative anesthetics (e.g., PCP), and naturally
occurring plant components (e.g., coca leaves and poppy straw). The mechanism(s) of
action of the above Schedule II substances are wholly different from one another, and
they are different from tetrahydrocannabinol (THC) and marijuana as well. For
9

 example, Schedule II stimulants typically function by increasing monoaminergic tone
via an increase in dopamine and norepinephrine (Schmitt et al., 2013). In contrast,
opioid analgesics function via mu-opioid receptor agonist effects. These differing
mechanism(s) of action result in vastly different behavioral and adverse effect profiles,
making comparisons across the range of pharmacologically diverse C-II substances
inappropriate.
In addition, many substances scheduled under the CSA are reviewed and evaluated
within the context of commercial drug development, using data submitted in the form
of a new drug application (NDA). A new analgesic drug might be compared to a
currently scheduled analgesic drug as part of the assessment of its relative abuse
potential. However, because the petitioners have not identified a specific indication
for the use of marijuana, identifying an appropriate comparator based on indication
cannot be done.
a. There is evidence that individuals are taking the substance in amounts
sufficient to create a hazard to their health or to the safety of other individuals or
to the community.
Evidence shows that some individuals are taking marijuana in amounts sufficient to
create a hazard to their health and to the safety of other individuals and the
community. A large number of individuals use marijuana. HHS provides data on the
extent of marijuana abuse through NIDA and the Substance Abuse and Mental Health
Services Administration (SAMHSA). According to the most recent data from
SAMHSA’s 2012 National Survey on Drug Use and Health (NSDUH), which
estimates the number of individuals who have used a substance within a month prior
to the study (described as “current use”), marijuana is the most commonly used illicit
drug among Americans aged 12 years and older, with an estimated 18.9 million
Americans having used marijuana within the month prior to the 2012 NSDUH.
Compared to 2004, when an estimated 14.6 million individuals reported using
marijuana within the month prior to the study, the estimated rates in 2012 show an
increase of approximately 4.3 million individuals. The 2013 Monitoring the Future
(MTF) survey of 8th, 10th, and 12th grade students also indicates that marijuana is the
most widely used illicit substance in this age group. Specifically, current month use
was at 7.0 percent of 8th graders, 18.0 percent of 10th, graders and 22.7 percent of 12th
graders. Additionally, the 2011 Treatment Episode Data Set (TEDS) reported that
primary marijuana abuse accounted for 18.1 percent of non-private substance-abuse
treatment facility admissions, with 24.3 percent of those admitted reporting daily use.
However, of these admissions for primary marijuana abuse, the criminal justice system
referred 51.6 percent to treatment. SAMHSA’s Drug Abuse Warning Network
(DAWN) was a national probability survey of U.S. hospitals with emergency
departments (EDs) and was designed to obtain information on ED visits in which
marijuana was mentioned, accounting for 36.4 percent of illicit drug related ED visits.
There are some limitations related to DAWN data on ED visits, which are discussed in
detail in Factor 4, “Its History and Current Pattern of Abuse;” Factor 5, “The Scope,
10

 Duration, and Significance of Abuse;” and Factor 6, “What, if any, Risk There is to
the Public Health.” These factors contain detailed discussions of these data.
A number of risks can occur with both acute and chronic use of marijuana. Detailed
discussions of the risks are addressed in Factor 2, “Scientific Evidence of its
Pharmacological Effect, if Known,” and Factor 6, “What, if any, Risk There is to the
Public Health.”

b. There is significant diversion of the substance from legitimate drug channels.
There is a lack of evidence of significant diversion of marijuana from legitimate drug
channels, but this is likely due to the fact that marijuana is more widely available from
illicit sources rather than through legitimate channels. Marijuana is not an FDAapproved drug product, as an NDA or biologics license application (BLA) has not
been approved for marketing in the United States. Numerous states and the District of
Columbia have state-level medical marijuana laws that allow for marijuana use within
that state. These state-level drug channels do not have sufficient collection of data
related to medical treatment, including efficacy and safety.
Marijuana is used by researchers for nonclinical research as well as clinical research
under investigational new drug (IND) applications; this represents the only legitimate
drug channel in the United States. However, marijuana used for research represents a
very small contribution of the total amount of marijuana available in the United States,
and thus provides limited information about diversion. In addition, the lack of
significant diversion of investigation supplies is likely because of the widespread
availability of illicit marijuana of equal or greater amounts of delta9-THC. The data
originating from the DEA on seizure statistics demonstrate the magnitude of the
availability for illicit marijuana. DEA’s System to Retrieve Information from Drug
Evidence (STRIDE) provides information on total domestic drug seizures. STRIDE
reports a total domestic seizure of 573,195 kg of marijuana in 2011, the most recent
year with complete data that is currently publically available (DEA Domestic Drug
Seizures, n.d.).
c. Individuals are taking the substance on their own initiative rather than on
the basis of medical advice from a practitioner licensed by law to administer such
substances.
Because the FDA has not approved an NDA or BLA for a marijuana drug product for
any therapeutic indication, the only way an individual can take marijuana on the basis
of medical advice through legitimate channels at the federal level is by participating in
research under an IND application. That said, numerous states and the District of
Columbia have passed state-level medical marijuana laws allowing for individuals to
use marijuana under certain circumstances. However, data are not yet available to
determine the number of individuals using marijuana under these state-level medical
marijuana laws. Regardless, according to the 2012 NSDUH data, 18.9 million
11

 American adults currently use marijuana (SAMHSA, 2013). Based on the large
number of individuals reporting current use of marijuana and the lack of an FDAapproved drug product in the United States, one can assume that it is likely that the
majority of individuals using marijuana do so on their own initiative rather than on the
basis of medical advice from a licensed practitioner.
d. The substance is so related in its action to a substance already listed as
having a potential for abuse to make it likely that it will have the same potential
for abuse as such substance, thus making it reasonable to assume that there may
be significant diversions from legitimate channels, significant use contrary to or
without medical advice, or that it has a substantial capability of creating hazards
to the health of the user or to the safety of the community.
FDA has approved two drug products containing cannabinoid compounds that are
structurally related to the active components in marijuana. These two marketed
products are controlled under the CSA. Once a specific drug product containing
cannabinoids becomes approved, that specific drug product may be moved from
Schedule I to a different Schedule (II – V) under the CSA. Firstly, Marinol—
generically known as dronabinol—is a Schedule III drug product containing synthetic
delta9-THC. Marinol, which is formulated in sesame oil in soft gelatin capsules, was
first placed in Schedule II under the CSA following its approval by the FDA. Marinol
was later rescheduled to Schedule III under the CSA because of low numbers of
reports of abuse relative to marijuana. Dronabinol is listed in Schedule I under the
CSA. FDA approved Marinol in 1985 for the treatment of nausea and vomiting
associated with cancer chemotherapy in patients who failed to respond adequately to
conventional anti-emetic treatments. In 1992, FDA approved Marional for anorexia
associated with weight loss in patients with acquired immunodeficiency syndrome
(AIDS). Secondly, in 1985, FDA approved Cesamet, a drug product containing the
Schedule II substance nabilone, for the treatment of nausea and vomiting associated
with cancer chemotherapy. Besides the two cannabinoid-containing drug products
FDA approved for marketing, other naturally occurring cannabinoids and their
derivatives (from Cannabis) and their synthetic equivalents with similar chemical
structure and pharmacological activity are included in the CSA as Schedule I
substances.

2. SCIENTIFIC EVIDENCE OF ITS PHARMACOLOGICAL EFFECTS, IF
KNOWN
Under the second factor, the Secretary must consider the scientific evidence of
marijuana's pharmacological effects. Abundant scientific data are available on the
neurochemistry, toxicology, and pharmacology of marijuana. This section includes a
scientific evaluation of marijuana’s neurochemistry; pharmacology; and human and
animal behavioral, central nervous system, cognitive, cardiovascular, autonomic,
endocrinological, and immunological system effects. The overview presented below
relies upon the most current research literature on cannabinoids.
12

 Neurochemistry and Pharmacology of Marijuana
Marijuana is a plant that contains numerous natural constituents, such as cannabinoids,
that have a variety of pharmacological actions. The petition defines marijuana as
including all Cannabis cultivated strains. Different marijuana samples derived from
various cultivated strains may have very different chemical constituents including
delta9-THC and other cannabinoids (Appendino et al., 2011). As a consequence,
marijuana products from different strains will have different biological and
pharmacological profiles.
According to ElSohly and Slade (2005) and Appendino et al. (2011), marijuana
contains approximately 525 identified natural constituents, including approximately
100 compounds classified as cannabinoids. Cannabinoids primarily exist in Cannabis,
and published data suggests that most major cannabinoid compounds occurring
naturally have been identified chemically. New and minor cannabinoids and other
new compounds are continuously being characterized (Pollastro et al., 2011). So far,
only two cannabinoids (cannabigerol and its corresponding acid) have been obtained
from a non-Cannabis source. A South African Helichrysum (H. umbraculigerum)
accumulates these compounds (Appendino et al., 2011). The chemistry of marijuana
is described in more detail in Factor 3, “The State of Current Scientific Knowledge
Regarding the Drug or Other Substance.”
The site of cannabinoid action is at the cannabinoid receptors. Cloning of cannabinoid
receptors, first from rat brain tissue (Matsuda et al., 1990) and then from human brain
tissue (Gerard et al., 1991), has verified the site of action. Two cannabinoid receptors,
CB1 and CB2, were characterized (Battista et al., 2012; Piomelli, 2005). Evidence of a
third cannabinoid receptor exists, but it has not been identified (Battista et al., 2012).
The cannabinoid receptors, CB1 and CB2, belong to the family of G-protein-coupled
receptors, and present a typical seven transmembrane-spanning domain structure.
Cannabinoid receptors link to an inhibitory G-protein (Gi), such that adenylate cyclase
activity is inhibited when a ligand binds to the receptor. This, in turn, prevents the
conversion of ATP to the second messenger, cyclic AMP (cAMP). Examples of
inhibitory coupled receptors include opioid, muscarinic cholinergic, alpha2adrenoreceptors, dopamine (D2), and serotonin (5-HT1).
Cannabinoid receptor activation inhibits N- and P/Q-type calcium channels and
activates inwardly rectifying potassium channels (Mackie et al., 1995; Twitchell et al.,
1997). N-type calcium channel inhibition decreases neurotransmitter release from
several tissues. Thus, calcium channel inhibition may be the mechanism by which
cannabinoids inhibit acetylcholine, norepinephrine, and glutamate release from
specific areas of the brain. These effects may represent a potential cellular mechanism
underlying cannabinoids' antinociceptive and psychoactive effects (Ameri, 1999).

13

 CB1 receptors are found primarily in the central nervous system, but are also present in
peripheral tissues. CB1 receptors are located mainly in the basal ganglia, hippocampus,
and cerebellum of the brain (Howlett et al., 2004). The localization of these receptors
may explain cannabinoid interference with movement coordination and effects on
memory and cognition. Additionally, CB1 receptors are found in the immune system
and numerous other peripheral tissues (Petrocellis and Di Marzo, 2009). However, the
concentration of CB1 receptors is considerably lower in peripheral tissues than in the
central nervous system (Herkenharn et al., 1990 and 1992).
CB2 receptors are found primarily in the immune system, but are also present in the
central nervous system and other peripheral tissues. In the immune system, CB2
receptors are found predominantly in B lymphocytes and natural killer cells
(Bouaboula et al., 1993). CB2 receptors may mediate cannabinoids' immunological
effects (Galiegue et al., 1995). Additionally, CB2 receptors have been localized in the
brain, primarily in the cerebellum and hippocampus (Gong et al., 2006). The
distribution of CB2 receptors throughout the body is less extensive than the
distribution of CB1 receptors (Petrocellis and Di Marzo, 2009). However, both CB1
and CB2 receptors are present in numerous tissues of the body.
Cannabinoid receptors have endogenous ligands. In 1992 and 1995, two endogenous
cannabinoid receptor agonists, anandamide and arachidonyl glycerol (2-AG),
respectively, were identified (Di Marzo, 2006). Anandamide is a low efficacy agonist
(Breivogel and Childers, 2000) and 2-AG is a high efficacy agonist (Gonsiorek et al.,
2000). Cannabinoid endogenous ligands are present in central as well as peripheral
tissues. A combination of uptake and hydrolysis terminate the action of the
endogenous ligands. The endogenous cannabinoid system is a locally active signaling
system that, to help restore homeostasis, is activated "on demand" in response to
changes to the local homeostasis (Petrocellis and Di Marzo, 2009). The endogenous
cannabinoid system, including the endogenous cannabinoids and the cannabinoid
receptors, demonstrate substantial plasticity in response to several physiological and
pathological stimuli (Petrocellis and Di Marzo, 2009). This plasticity is particularly
evident in the central nervous system.
Delta9-THC and cannabidiol (CBD) are two abundant cannabinoids present in
marijuana. Marijuana's major psychoactive cannabinoid is delta9-THC (Wachtel et al.,
2002). In 1964, Gaoni and Mechoularn first described delta9-THC's structure and
function. In 1963, Mechoularn and Shvo first described CBD's structure. The
pharmacological actions of CBD have not been fully studied in humans.
Delta9-THC and CBD have varying affinity and effects at the cannabinoid receptors.
Delta9-THC displays similar affinity for CB1 and CB2 receptors, but behaves as a
weak agonist for CB2 receptors. The identification of synthetic cannabinoid ligands
that selectively bind to CB2 receptors but do not have the typical delta9-THC-like
psychoactive properties suggests that the activation of CB1-receptors mediates
cannabinoids' psychotropic effects (Hanus et al., 1999). CBD has low affinity for both
CB1 and CB2 receptors (Mechoulam et al., 2007). According to Mechoulam et al.
14

 (2007), CBD has antagonistic effects at CB1 receptors and some inverse agonistic
properties at CB2 receptors. When cannabinoids are given subacutely to rats, CB1
receptors down-regulate and the binding of the second messenger system coupled to
CB1 receptors, GTPgarnmaS, decreases (Breivogel et al., 2001).
Animal Behavioral Effects
Self-Administration
Self-administration is a method that assesses the ability of a drug to produce rewarding
effects. The presence of rewarding effects increases the likelihood of behavioral
responses to obtain additional drug. Animal self-administration of a drug is often
useful in predicting rewarding effects in humans, and is indicative of abuse liability. A
good correlation is often observed between those drugs that rhesus monkeys selfadminister and those drugs that humans abuse (Balster and Bigelow, 2003). Initially,
researchers could not establish self-administration of cannabinoids, including delta9THC, in animal models. However, self-administration of delta9 -THC can now be
established in a variety of animal models under specific training paradigms (Justinova
et al., 2003, 2004, 2005).
Squirrel monkeys, with and without prior exposure to other drugs of abuse, selfadminister delta9-THC under specific conditions. For instance, Tanda et al. (2000)
observed that when squirrel monkeys are initially trained to self-administer
intravenous cocaine, they will continue to bar-press delta9-THC at the same rate as
they would with cocaine. The doses were notably comparable to those doses used by
humans who smoke marijuana. SR141716, a CB1 cannabinoid receptor agonistantagonist, can block this rewarding effect. Other studies show that naïve squirrel
monkeys can be successfully trained to self-administer delta9-THC intravenously
(Justinova et al., 2003). The maximal responding rate is 4 μg/kg per injection, which is
2-3 times greater than observed in previous studies using cocaine-experienced
monkeys. Naltrexone, a mu-opioid antagonist, partially antagonizes these rewarding
effects of delta9-THC (Justinova et al., 2004).
Additionally, data demonstrate that under specific conditions, rodents self-administer
cannabinoids. Rats will self-administer delta9-THC when applied
intracerebroventricularly (i.c.v.), but only at the lowest doses tested (0.01-0.02 μg
/infusion) (Braida et al., 2004). SR141716 and the opioid antagonist naloxone can
antagonize this effect. However, most studies involve rodents self-administrating the
synthetic cannabinoid WIN 55212, a CB1 receptor agonist with a non-cannabinoid
structure (Deiana et al., 2007; Fattore et al., 2007; Martellotta et al., 1998; Mendizabal
et al., 2006).
Aversive effects, rather than reinforcing effects, occur in rats that received high doses
of WIN 55212 (Chaperon et al., 1998) or delta9-THC (Sanudo-Pena et al., 1997),
indicating a possible critical dose-dependent effect. In both studies, SR141716
reversed these aversive effects.
15

 Conditioned Place Preference
Conditioned place preference (CPP) is a less rigorous method than self-administration
for determining whether or not a drug has rewarding properties. In this behavioral test,
animals spend time in two distinct environments: one where they previously received
a drug and one where they received a placebo. If the drug is reinforcing, animals will
choose to spend more time in the environment paired with the drug, rather than with
the placebo, when presented with both options s.imultaneously.
Animals show CPP to delta9-THC, but only at the lowest doses tested (0.075-1.0
mg/kg, intraperitoneal (i.p.)) (Braida et al., 2004). SR141716 and naloxone antagonize
this effect (Braida et al., 2004). As a partial agonist, SR141716 can induce CPP at
doses of 0.25, 0.5, 2 and 3 mg/kg (Cheer et al., 2000). In knockout mice, those without
μ-opioid receptors do not develop CPP to delta9-THC (Ghozland et al., 2002).
Drug Discrimination Studies
Drug discrimination is a method where animals indicate whether a test drug produces
physical or psychic perceptions similar to those produced by a known drug of abuse.
In this test, an animal learns to press one bar when it receives the known drug of abuse
and another bar when it receives placebo. To determine whether the test drug is like
the known drug of abuse, a challenge session with the test drug demonstrates which of
the two bars the animal presses more often.
In addition to humans (Lile et al., 2009; Lile et al., 2011), it has been noted that
animals, including monkeys (McMahon, 2009), mice (McMahon et al., 2008), and rats
(Gold et al., 1992), are able to discriminate cannabinoids from other drugs or placebo.
Moreover, the major active metabolite of delta9-THC, 11-hydroxy-delta9-THC, also
generalizes (following oral administration) to the stimulus cues elicited by delta9-THC
(Browne and Weissman, 1981). Twenty-two other cannabinoids found in marijuana
also fully substitute for delta9-THC. However, CBD does not substitute for delta9-THC
in rats (Vann et al., 2008).
Discriminative stimulus effects of delta9-THC are pharmacologically specific for
marijuana containing cannabinoids (Balster and Prescott, 1992; Browne and
Weissman, 1981; Wiley et al., 1993, 1995). The discriminative stimulus effects of the
cannabinoid group appear to provide unique effects because stimulants, hallucinogens,
opioids, benzodiazepines, barbiturates, NMDA antagonists, and antipsychotics do not
fully substitute for delta9-THC.
Central Nervous System Effects
Human Physiological and Psychological Effects
Psychoactive Effects
16

 Below is a list of the common subjective responses to cannabinoids (Adams and
Martin, 1996; Gonzalez, 2007; Hollister 1986, 1988; Institute of Medicine, 1982).
According to Maldonado (2002), these responses to marijuana are pleasurable to many
humans and are often associated with drug-seeking and drug-taking. High levels of
positive psychoactive effects are associated with increased marijuana use, abuse, and
dependence (Scherrer et al., 2009; Zeiger et al., 2010).
1) Disinhibition, relaxation, increased sociability, and talkativeness.
2) Increased merriment and appetite, and even exhilaration at high doses.
3) Enhanced sensory perception, which can generate an increased appreciation of
music, art, and touch.
4) Heightened imagination, which can lead to a subjective sense of increased
creativity.
5) Initial dizziness, nausea, tachycardia, facial flushing, dry mouth, and tremor.
6) Disorganized thinking, inability to converse logically, time distortions, and
short-term memory impairment.
7) Ataxia and impaired judgment, which can impede driving ability or lead to an
increase in risk-tasking behavior.
8) Illusions, delusions, and hallucinations that intensify with higher doses.
9) Emotional lability, incongruity of affect, dysphoria, agitation, paranoia,
confusion, drowsiness, and panic attacks, which are more common in
inexperienced or high-dosed users.
As with many psychoactive drugs, a person's medical, psychiatric, and drug-taking
history can influence the individual's response to marijuana. Dose preferences to
marijuana occur in that marijuana users prefer higher concentrations of the principal
psychoactive substance (1.95 percent delta9-THC) over lower concentrations (0.63
percent delta9-THC) (Chait and Burke, 1994). Nonetheless, frequent marijuana users
(> 100 times of use) were able to identify a drug effect from low-dose delta9-THC
better than occasional users (<10 times of use) while also experiencing fewer sedative
effects from marijuana (Kirk and de Wit, 1999).
The petitioners contend that many of marijuana's naturally occurring cannabinoids
mitigate the psychoactive effects of delta9-THC, and therefore that marijuana lacks
sufficient abuse potential to warrant Schedule I placement, because Marinol, which is
in Schedule III, contains only delta9-THC. This theory has not been demonstrated in
controlled studies. Moreover, the concept of abuse potential encompasses all
properties of a substance, including its chemistry, pharmacology, and
pharmacokinetics, as well as usage patterns and diversion history. The abuse potential
of a substance is associated with the repeated or sporadic use of a substance in
nonmedical situations for the psychoactive effects the substance produces. These
psychoactive effects include euphoria, perceptual and other cognitive distortions,
hallucinations, and mood changes. However, as stated above, the abuse potential not
only includes the psychoactive effects, but also includes other aspects related to a
substance.
17

 DEA's final published rule entitled "Rescheduling of the Food and Drug
Administration Approved Product Containing Synthetic Dronabinol [(-)-delta9-(trans)Tetrahydrocannabinol] in Sesame Oil and Encapsulated in Soft Gelatin Capsules From
Schedule II to Schedule III" (64 FR 35928, July 2, 1999) rescheduled Marinol from
Schedule II to Schedule III. The HHS assessment of the abuse potential and
subsequent scheduling recommendation compared Marinol to marijuana on different
aspects related to abuse potential. Major differences in formulation, availability, and
usage between marijuana and the drug product, Marinol, contribute to their differing
abuse potentials.
Hollister and Gillespie (1973) estimated that delta9-THC by smoking is 2.6 to 3 times
more potent than delta9-THC ingested orally. The intense psychoactive drug effect
achieved, rapidly by smoking is generally considered to produce the effect desired by
the abuser. This effect explains why abusers often prefer to administer certain drugs
by inhalation, intravenously, or intranasally rather than orally. Such is the case with
cocaine, opium, heroin, phencyclidine, methamphetamine, and delta9-THC from
marijuana (0.1-9.5 percent delta9-THC range) or hashish (10-30 percent delta9-THC
range) (Wesson and Washburn, 1990). Thus, the delayed onset and longer duration of
action for Marinol may be contributing factors limiting the abuse or appeal of Marinol
as a drug of abuse relative to marijuana.
The formulation of Marinol is a factor that contributes to differential scheduling of
Marinol and marijuana. For example, extraction and purification of dronabinol from
the encapsulated sesame oil mixture of Marinol is highly complex and difficult.
Additionally, the presence of sesame oil mixture in the formulation may preclude the
smoking of Marinol-laced cigarettes.
Additionally, there is a dramatic difference between actual abuse and illicit trafficking
of Marinol and marijuana. Despite Marinol's availability in the United States, there
have been no significant reports of abuse, diversion, or public health problems due to
Marinol. By comparison, 18.9 million American adults report currently using
marijuana (SAMHSA, 2013).
In addition, FDA's approval of an NDA for Marinol allowed for Marinol to be
rescheduled to Schedule II, and subsequently to Schedule III of the CSA. In
conclusion, marijuana and Marinol differ on a wide variety of factors that contribute to
each substance's abuse potential. These differences are major reasons distinguishing
the higher abuse potential for marijuana and the different scheduling determinations of
marijuana and Marinol.
In terms of the petitioners' claim that different cannabinoids present in marijuana
mitigate the psychoactive effects of delta9-THC, only three of the cannabinoids
present in marijuana were simultaneously administered with delta9-THC to examine
how the combinations of these cannabinoids such as CBD, cannabichromene (CBC)
and cannabinol (CBN) influence delta9-THC's psychoactive effects. Dalton et al.
18

 (1976) observed that smoked administration of placebo marijuana cigarettes
containing injections of 0.15 mg/kg CBD combined with 0.025mg/kg of delta9-THC,
in a 7:1 ratio of CBD to delta9-THC, significantly decreased ratings of acute subjective
effects and "high" when compared to smoking delta9-THC alone. In contrast, Ilan et
al. (2005) calculated the naturally occurring concentrations of CBC and CBD in a
batch of marijuana cigarettes with either 1.8 percent or 3.6 percent delta9-THC
concentration by weight. For each strength of delta9-THC in marijuana cigarettes, the
concentrations of CBC and CBD were classified in groups of either low or high. The
study varied the amount of CBC and CBD within each strength of delta9-THC
marijuana cigarettes, with administrations consisting of either low CBC (between 0.10.2 percent CBC concentration by weight) and low CBD (between 0.1-0.4 percent
CBD concentration by weight), high CBC (>0.5 percent CBC concentration by
weight) and low CBD, or low CBC and high CBD (>1.0 percent CBD concentration
by weight). Overall, all combinations scored significantly greater than placebo on
ratings of subjective effects, and there was no significant difference between any
combinations.
The oral administration of a combination of either 15, 30, or 60 mg CBD with 30 mg
delta9-THC dissolved in liquid (in a ratio of at least 1:2 CBD to delta9-THC) reduced
the subjective effects produced by delta9-THC alone (Karniol et al., 1974).
Additionally, orally administering a liquid mixture combining 1 mg/kg CBD with 0.5
mg/kg of delta9-THC (ratio of 2:1 CBD to delta9-THC) decreased scores of anxiety
and marijuana drug effect on the Addiction Research Center Inventory (ARCI)
compared to delta9-THC alone (Zuardi et al.,1982). Lastly, oral administration of
either 12.5, 25, or 50 mg CBN combined with 25 mg delta9-THC dissolved in liquid
(ratio of at least 1:2 CBN to delta9-THC) significantly increased subjective ratings of
"drugged," "drowsy," "dizzy," and "drunk," compared to delta9-THC alone (Karniol et
al., 1975).
Even though some studies suggest that CBD may decrease some of delta9-THC's
psychoactive effects, the ratios of CBD to delta9-THC administered in these studies
are not present in marijuana used by most people. For example, in one study,
researchers used smoked marijuana with ratios of CBD to delta9-THC naturally
present in marijuana plant material and they found out that varying the amount of
CBD actually had no effect on delta9-THC's psychoactive effects (Ilan et al., 2005).
Because most marijuana currently available on the street has high amounts of delta9THC with low amounts of CBD and other cannabinoids, most individuals use
marijuana with low levels of CBD present (Mehmedic et al., 2010). Thus, any possible
mitigation of delta9-THC's psychoactive effects by CBD will not occur for most
marijuana users. In contrast, one study indicated that another cannabinoid present in
marijuana, CBN, may enhance delta9-THC's psychoactive effects (Karniol et al.,1975).
Behavioral Impairment
Marijuana induces various psychoactive effects that can lead to behavioral
impairment. Marijuana's acute effects can significantly interfere with a person's ability
19

 to learn in the classroom or to operate motor vehicles. Acute administration of smoked
marijuana impairs performance on learning, associative processes, and psychomotor
behavioral tests (Block et al., 1992). Ramaekers et al. (2006a) showed that acute
administration of 250 μg/kg and 500 μg/kg of delta9-THC in smoked marijuana dosedependently impairs cognition and motor control, including motor impulsivity and
tracking impairments (Ramaekers et al., 2006b). Similarly, administration of 290
μg/kg delta9-THC in a smoked marijuana cigarette resulted in impaired perceptual
motor speed and accuracy: two skills which are critical to driving ability (Kurzthaler et
al., 1999). Lastly, administration of 3.95 percent delta9-THC in a smoked marijuana
cigarette not only increased disequilibrium measures, but also increased the latency in
a task of simulated vehicle braking at a rate comparable to an increase in stopping
distance of five feet at 60 mph (Liguori et al., 1998). However, acute administration of
marijuana containing 2.1 percent delta9-THC does not produce "hangover effects"
(Chait, 1990).
In addition to measuring the acute effects immediately following marijuana
administration, researchers have conducted studies to determine how long behavioral
impairments last after abstinence. Some of marijuana's acute effects may not fully
resolve until at least one day after the acute psychoactive effects have subsided.
Heishman et al. (1990) showed that impairment on memory tasks persists for 24 hours
after smoking marijuana cigarettes containing 2.57 percent delta9-THC. However,
Fant et al. (1998) showed that the morning after exposure to 1.8 percent or 3.6 percent
smoked delta9-THC, subjects had minimal residual alterations in subjective or
performance measures.
A number of factors may influence marijuana's behavioral effects including the
duration of use (chronic or short term), frequency of use (daily, weekly, or
occasionally), and amount of use (heavy or moderate). Researchers also have
examined how long behavioral impairments last following chronic marijuana use.
These studies used self-reported histories of past duration, frequency, and amount of
past marijuana use, and administered a variety of performance and cognitive measures
at different time points following marijuana abstinence. In chronic marijuana users,
behavioral impairments may persist for up to 28 days of abstinence. Solowij et al.
(2002) demonstrated that after 17 hours of abstinence, 51 adult heavy chronic
marijuana users performed worse on memory and attention tasks than 33 non-using
controls or 51 heavy, short-term users. Another study noted that heavy, frequent
marijuana users, abstinent for at least 24 hours, performed significantly worse than the
controls on verbal memory and psychomotor speed tests (Messinis et al., 2006).
Additionally, after at least 1 week of abstinence, young adult frequent marijuana users,
aged 18-28, showed deficits in psychomotor speed, sustained attention, and cognitive
inhibition (Lisdahl and Price, 2012). Adult heavy, chronic marijuana users showed
deficits on memory tests after 7 days of supervised abstinence (Pope et al., 2002).
However, when these same individuals were again tested after 28 days of abstinence,
they did not show significant memory deficits. The authors concluded, "cannabisassociated cognitive deficits are reversible and related to recent cannabis exposure,
20

 rather than irreversible and related to cumulative lifetime use."7 However, other
researchers reported neuropsychological deficits in memory, executive functioning,
psychomotor speed and manual dexterity in heavy marijuana users abstinent for 28
days (Bolla et al., 2002). Furthermore, a follow-up study of heavy marijuana users
noted decision-making deficits after 25 days of supervised abstinence. (Bolla et al.,
2005). However, moderate marijuana users did not show decision-making deficits
after 25 days of abstinence, suggesting the amount of marijuana use may impact the
duration of residual impairment.
The effects of chronic marijuana use do not seem to persist after more than 1 to 3
months of abstinence. After 3 months of abstinence, any deficits observed in IQ,
immediate memory, delayed memory, and information-processing speeds following
heavy marijuana use compared to pre-drug use scores were no longer apparent (Fried
et al., 2005). Marijuana did not appear to have lasting effects on performance of a
comprehensive neuropsychological battery when 54 monozygotic male twins (one of
whom used marijuana, one of whom did not) were compared 1-20 years after
cessation of marijuana use (Lyons et al., 2004). Similarly, following abstinence for a
year or more, both light and heavy adult marijuana users did not show deficits on
scores of verbal memory compared to non-using controls (Tait et al., 2011). According
to a recent meta-analysis looking at non-acute and long-lasting effects of marijuana
use on neurocognitive performance, any deficits seen within the first month following
abstinence are generally not present after about 1 month of abstinence (Schreiner and
Dunn, 2012).
Another aspect that may be a critical factor in the intensity and persistence of
impairment resulting from chronic marijuana use is the age of first use. Individuals
with a diagnosis of marijuana misuse or dependence who were seeking treatment for
substance use, who initiated marijuana use before the age of 15 years, showed deficits
in performance on tasks assessing sustained attention, impulse control, and general
executive functioning compared to non-using controls. These deficits were not seen in
individuals who initiated marijuana use after the age of 15 years (Fontes et al., 2011).
Similarly, heavy, chronic marijuana users who began using marijuana before the age
of 16 years had greater decrements in executive functioning tasks than heavy, chronic
marijuana users who started using after the age of 16 years and non-using controls
(Gruber et al., 2012). Additionally, in a prospective longitudinal birth cohort study of
1,037 individuals, marijuana dependence or chronic marijuana use was associated with
a decrease in IQ and general neuropsychological performance compared to premarijuana exposure levels in adolescent onset users (Meier et al., 2012). The decline
in adolescent-onset user's IQ persisted even after reduction or abstinence of marijuana
use for at least 1 year. In contrast, the adult-onset chronic marijuana users showed no
significant changes in IQ compared to pre-exposure levels whether they were current
users or abstinent for at least 1 year (Meier et al., 2012).

7

In this quotation the term Cannabis is used interchangeably for marijuana.

21

 In addition to the age of onset of use, some evidence suggests that the amount of
marijuana used may relate to the intensity of impairments. In the above study by
Gruber et al. (2012), where early-onset users had greater deficits than late-onset users,
the early-onset users reported using marijuana twice as often and using three times as
much marijuana per week than the late-onset users. Meier et al. (2012) showed that the
deficits in IQ seen in adolescent-onset users increased with the amount of marijuana
used. Moreover, when comparing scores for measures of IQ, immediate memory,
delayed memory, and information-processing speeds to pre-drug-use levels, the
current, heavy, chronic marijuana users showed deficits in all three measures while
current, occasional marijuana users did not (Fried et al., 2005).
Behavioral Effects of Prenatal Exposure
Studies with children at different stages of development are used to examine the
impact of prenatal marijuana exposure on performance in a series of cognitive tasks.
However, many pregnant women who reported marijuana use were more likely to also
report use of alcohol, tobacco, and cocaine (Goldschmidt et al., 2008). Thus, with
potential exposure to multiple drugs, it is difficult to determine the specific impact of
prenatal marijuana exposure.
Most studies assessing the behavioral effects of prenatal marijuana exposure included
women who, in addition to using marijuana, also reported using alcohol and tobacco.
However, some evidence suggests an association between heavy prenatal marijuana
exposure and deficits in some cognitive domains. In both 4-year-old and 6-year-old
children, heavy prenatal marijuana use is negatively associated with performance on
tasks assessing memory, verbal reasoning, and quantitative reasoning (Fried and
Watkinson, 1987; Goldschmidt et al., 2008). Additionally, heavy prenatal marijuana
use is associated with deficits in measures of sustained attention in children at the ages
of 6 years and 13-16 years (Fried et al., 1992; Fried, 2002). In 9- to 12-year-old
children, prenatal marijuana exposure is negatively associated with executive
functioning tasks that require impulse control, visual analysis, and hypothesis (Fried et
al., 1998).
Association of Marijuana Use with Psychosis
This analysis evaluates only the evidence for a direct link between prior marijuana use
and the subsequent development of psychosis. Thus, this discussion does not consider
issues such as whether marijuana's transient effects are similar to psychotic symptoms
in healthy individuals or exacerbate psychotic symptoms in individuals already
diagnosed with schizophrenia.
Extensive research has been conducted to investigate whether exposure to marijuana is
associated with the development of schizophrenia or other psychoses. Although many
studies are small and inferential, other studies in the literature use hundreds to
thousands of subjects. At present, the available data do not suggest a causative link
between marijuana use and the development of psychosis (Minozzi et al., 2010).
22

 Numerous large, longitudinal studies show that subjects who used marijuana do not
have a greater incidence of psychotic diagnoses compared to those who do not use
marijuana (Fergusson et al., 2005; Kuepper et al., 2011; Van Os et al., 2002).
When analyzing the available evidence of the connection between psychosis and
marijuana, it is critical to determine whether the subjects in the studies are patients
who are already diagnosed with psychosis or individuals who demonstrate a limited
number of symptoms associated with psychosis without qualifying for a diagnosis of
the disorder. For example, instead of using a diagnosis of psychosis, some researchers
relied on non-standard methods of representing symptoms of psychosis including
"schizophrenic cluster" (Maremmani et al., 2004), "subclinical psychotic symptoms"
(Van Gastel et al., 2012), "pre-psychotic clinical high risk" (Van der Meer et al.,
2012), and symptoms related to "psychosis vulnerability" (Griffith-Lendering et al.,
2012). These groupings do not conform to the criteria in the Diagnostic and Statistical
Manual (DSM-5) or the International Classification of Diseases (ICD-10) for a
diagnosis of psychosis. Thus, these groupings are not appropriate for use in evaluating
marijuana's impact on the development of actual psychosis. Accordingly, this analysis
includes only those studies that use subjects diagnosed with a psychotic disorder.
In the largest study evaluating the link between psychosis and drug use, 274 of the
approximately 45,500 Swedish conscripts in the study population (<0.01 percent)
received a diagnosis of schizophrenia within the 14-year period following military
induction from 1969 to 1983 (Andreasson et al., 1987). Of the conscripts diagnosed
with psychosis, 7.7 percent (21 of the 274 conscripts with psychosis) had used
marijuana more than 50 times at induction, while 72 percent (197 of the 274 conscripts
with psychosis) had never used marijuana. Although high marijuana use increased the
relative risk for schizophrenia to 6.0, the authors note that substantial marijuana use
history "accounts for only a minority of all cases" of psychosis (Andreasson et al.,
1987). Instead, the best predictor for whether a conscript would develop psychosis
was a non-psychotic psychiatric diagnosis upon induction. The authors concluded that
marijuana use increased the risk for psychosis only among individuals predisposed to
develop the disorder. In addition, a 35-year follow up to this study reported very
similar results (Manrique-Garcia et al., 2012). In this follow up study, 354 conscripts
developed schizophrenia; of these 354 conscripts, 32 used marijuana more than 50
times at induction (9 percent, an odds ratio of 6.3), while 255 had never used
marijuana (72 percent).
Additionally, the conclusion that the impact of marijuana may manifest only in
individuals likely to develop psychotic disorders has been shown in many other types
of studies. For example, although evidence shows that marijuana use may precede the
presentation of symptoms in individuals later diagnosed with psychosis
(Schimmelmann et al., 2011), most reports conclude that prodromal symptoms of
schizophrenia appear prior to marijuana use (Schiffman et al., 2005). Similarly, a
review of the gene-environment interaction model for marijuana and psychosis
concluded that some evidence supports marijuana use as a factor that may influence
23

 the development of psychosis, but only in those individuals with psychotic liability
(Pelayo-Teran et al., 2012).
A similar conclusion was drawn when the prevalence of schizophrenia was modeled
against marijuana use across eight birth cohorts in Australia in individuals born
between the years 1940 to 1979 (Degenhardt et al., 2003). Although marijuana use
increased over time in adults born during the four-decade period, there was not a
corresponding increase in diagnoses for psychosis in these individuals. The authors
conclude that marijuana may precipitate schizophrenic disorders only in those
individuals who are vulnerable to developing psychosis. Thus, marijuana per se does
not appear to induce schizophrenia in the majority of individuals who have tried or
continue to use marijuana. However, in individuals with a genetic vulnerability for
psychosis, marijuana use may influence the development of psychosis.
Cardiovascular and Autonomic Effects
Single smoked or oral doses of delta9-THC produce tachycardia and may increase
blood pressure (Capriotti et al., 1988; Benowitz and Jones, 1975). Some evidence
associates the tachycardia produced by delta9-THC with excitation of the sympathetic
and depression of the parasympathetic nervous systems (Malinowska et al., 2012).
During chronic marijuana ingestion, a tolerance to tachycardia develops (Malinowska
et al., 2012).
However, prolonged delta9-THC ingestion produces bradycardia and hypotension
(Benowitz and Jones, 1975). Plant-derived cannabinoids and endocannabinoids elicit
hypotension and bradycardia via activation of peripherally-located CB1 receptors
(Wagner et al., 1998). Specifically, the mechanism of this effect is through presynaptic
CB1 receptor-mediated inhibition of norepinephrine release from peripheral
sympathetic nerve terminals, with possible additional direct vasodilation via activation
of vascular cannabinoid receptors (Pacher et al., 2006). In humans, tolerance can
develop to orthostatic hypotension (Jones, 2002; Sidney, 2002) possibly related to
plasma volume expansion, but tolerance does not develop to the supine hypotensive
effects (Benowitz and Jones, 1975). Additionally, electrocardiographic changes are
minimal, even after large cumulative doses of delta9-THC are administered. (Benowitz
and Jones, 1975).
Marijuana smoking by individuals, particularly those with some degree of coronary
artery or cerebrovascular disease, poses risks such as increased cardiac work,
catecholamines and carboxyhemoglobin, myocardial infarction, and postural
hypotension (Benowitz and Jones, 1981; Hollister, 1988; Mittleman et al., 2001;
Malinowska et al., 2012).
Respiratory Effects
After acute exposure to marijuana, transient bronchodilation is the most typical
respiratory effect (Gong et al., 1984). A recent 20-year longitudinal study with over
24

 5,000 individuals collected information on the amount of marijuana use and
pulmonary function data at years 0, 2, 5, 10, and 20 (Pletcher et al., 2012). Among the
more than 5,000 individuals who participated in the study, almost 800 of them
reported current marijuana use but not tobacco use at the time of assessment. Pletcher
et al. (2012) found that the occasional use of marijuana is not associated with
decreased pulmonary function. However, some preliminary evidence suggests that
heavy marijuana use may be associated with negative pulmonary effects (Pletcher et
al., 2012). Long-term use of marijuana can lead to chronic cough and increased
sputum, as well as an increased frequency of chronic bronchitis and pharyngitis. In
addition, pulmonary function tests reveal that large-airway obstruction can occur with
chronic marijuana smoking, as can cellular inflammatory histopathological
abnormalities in bronchial epithelium (Adams and Martin 1996; Hollister 1986).
Evidence regarding marijuana smoking leading to cancer is inconsistent, as some
studies suggest a positive correlation while others do not (Lee and Hancox, 2011;
Tashkin, 2005). Several lung cancer cases have been reported in young marijuana
users with no tobacco smoking history or other significant risk factors (Fung et al.,
1999). Marijuana use may dose-dependently interact with mutagenic sensitivity,
cigarette smoking, and alcohol use to increase the risk of head and neck cancer (Zhang
et al., 1999). However, in a large study with 1,650 subjects, a positive association was
not found between marijuana and lung cancer (Tashkin et al., 2006). This finding
remained true, regardless of the extent of marijuana use, when controlling for tobacco
use and other potential confounding variables. Overall, new evidence suggests that the
effects of marijuana smoking on respiratory function and carcinogenicity differ from
those of tobacco smoking (Lee and Hancox, 2011).
Endocrine System
Experimental marijuana administration to humans does not consistently alter many
endocrine parameters. In an early study, male subjects who experimentally received
smoked marijuana showed a significant depression in luteinizing hormone and a
significant increase in cortisol (Cone et al., 1986). However, two later studies showed
no changes in hormones. Male subjects experimentally exposed to smoked delta9-THC
(18 mg/marijuana cigarette) or oral delta9-THC (10 mg three times per day for 3 days
and on the morning of the fourth day) showed no changes in plasma
adrenocorticotropic hormone (ACTH), cortisol, prolactin, luteinizing hormone, or
testosterone levels (Dax et al., 1989). Similarly, a study with 93 men and 56 women
showed that chronic marijuana use did not significantly alter concentrations of
testosterone, luteinizing hormone, follicle stimulating hormone, prolactin, or cortisol
(Block et al., 1991). Additionally, chronic marijuana use did not affect serum levels of
thyrotropin, thyroxine, and triiodothyronine (Bonnet, 2013). However, in a doubleblind, placebo-controlled, randomized clinical trial of HIV-positive men, smoking
marijuana dose-dependently increased plasma levels of ghrelin and leptin, and
decreased plasma levels of peptide YY (Riggs et al., 2012).

25

 The effects of marijuana on female reproductive system functionality differ between
humans and animals. In monkeys, delta9-THC administration suppressed ovulation
(Asch et al., 1981) and reduced progesterone levels (Almirez et al., 1983). However,
in women, smoked marijuana did not alter hormone levels or the menstrual cycle
(Mendelson and Mello, 1984). Brown and Dobs (2002) suggest that the development
of tolerance in humans may be the cause of the discrepancies between animal and
human hormonal response to cannabinoids.
The presence of in vitro delta9-THC reduces binding of the corticosteroid,
dexamethasone, in hippocampal tissue from adrenalectomized rats, suggesting an
interaction with the glucocorticoid receptor (Eldridge et al., 1991). Although acute
delta9-THC presence releases corticosterone, tolerance develops in rats with chronic
administration (Eldridge et al., 1991).
Some studies support a possible association between frequent, long-term marijuana
use and increased risk of testicular germ cell tumors (Trabert et al., 2011). On the
other hand, recent data suggest that cannabinoid agonists may have therapeutic value
in the treatment of prostate cancer, a type of carcinoma in which growth is stimulated
by androgens. Research with prostate cancer cells shows that the mixed CB1/CB2
agonist, WIN-55212-2, induces apoptosis in prostate cancer cells, as well as decreases
the expression of androgen receptors and prostate-specific antigens (Sarfaraz et al.,
2005).
Immune System
Cannabinoids affect the immune system in many different ways. Synthetic, natural,
and endogenous cannabinoids often cause different effects in a dose-dependent
biphasic manner (Croxford and Yamamura, 2005; Tanasescu and Constantinescu,
2010).
Studies in humans and animals give conflicting results about cannabinoid effects on
immune functioning in subjects with compromised immune systems. Abrams et al.
(2003) investigated marijuana's effect on immunological functioning in 62 AIDS
patients taking protease inhibitors. Subjects received one of the following three times a
day: a smoked marijuana cigarette containing 3.95 percent delta9-THC, an oral tablet
containing delta9-THC (2.5 mg oral dronabinol), or an oral placebo. The results
showed no changes in CD4+ and CD8+ cell counts, HIV RNA levels, or protease
inhibitor levels between groups. Thus, the use of cannabinoids showed no short-term
adverse virologic effects in individuals with compromised immune systems. However,
these human data contrast with data generated in immunodeficient mice, which
demonstrated that exposure to delta9-THC in vivo suppresses immune function,
increases HIV co-receptor expression, and acts as a cofactor to enhance HIV
replication (Roth et al., 2005).

3. THE STATE OF CURRENT SCIENTIFIC KNOWLEDGE REGARDING THE
DRUG OR OTHER SUBSTANCE
26

 Under the third factor, the Secretary must consider the state of current scientific
knowledge regarding marijuana. Thus, this section discusses the chemistry, human
pharmacokinetics, and medical uses of marijuana.
Chemistry
Marijuana is one of the common names of Cannabis sativa L. in the family
Cannabaceae.
Cannabis is one of the oldest cultivated crops, providing a source of fiber, food, oil,
and drug. Botanists still debate whether Cannabis should be considered as a single
(The Plant List, 2010) or three species, i.e., C. sativa, C. indica, and C. ruderalis
(Hillig, 2005). Specifically, marijuana is developed as sativa and indica cultivated
varieties (strains) or various hybrids.
The petition defines marijuana as including all Cannabis cultivated strains. Different
marijuana samples derived from various cultivated strains may have very different
chemical constituents including delta9 -THC and other cannabinoids (Appendino et al.,
2011). As a consequence, marijuana products from different strains will have different
safety, biological, pharmacological, and toxicological profiles. Thus, all Cannabis
strains cannot be considered together because of the varying chemical constituents
between strains.
Marijuana contains numerous naturally occurring constituents including cannabinoids.
Overall, various Cannabis strains contain more than 525 identified natural
constituents. Among those constituents, the most important ones are the 21 (or 22)
carbon terpenoids found in the plant, as well as their carboxylic acids, analogues, and
transformation products, known as cannabinoids (Agurell et al., 1984, 1986;
Mechoulam, 1973; Appendino et al., 2011). Thus far, more than 100 compounds
classified as cannabinoids have been characterized (ElSohly and Slade, 2005; Radwan,
ElSohly et al., 2009; Appendino et al. 2011).
Cannabinoids primarily exist in Cannabis, and published data suggest that most major
cannabinoid compounds occurring naturally have been chemically identified. New and
minor cannabinoids and other new compounds are continuously being characterized
(Pollastro et al., 2011). So far, only two cannabinoids (cannabigerol and its
corresponding acid) have been obtained from a non-Cannabis source. A South African
Helichrysum (H umbraculigerum) accumulates these compounds (Appendino et al.
2011).
Among the cannabinoids found in marijuana, delta9-THC (alternate name delta1-THC)
and delta-8-tetrahydrocannibinol (delta8-THC, alternate name delta6-THC) produce
marijuana's characteristic psychoactive effects. Because delta9-THC is more abundant
than delta8-THC, marijuana's psychoactivity is largely attributed to the former. Only a
few varieties of marijuana analyzed contain delta8-THC at significant amounts (Hively
et al., 1966). Delta9-THC is an optically active resinous substance, insoluble in water,
27

 and extremely lipid soluble. Chemically, delta9-THC is (6aR-trans)-6a,7,8,10atetrahydro-6,6,9-trimethyl-3-pentyl-6H-dibenzo-[b,d]pyran-l-ol, or (-)-delta9-(trans)tetrahydrocannabinol. The (-)-trans isomer of delta9-THC is pharmacologically 6-100
times more potent than the (+)-trans isomer (Dewey et al., 1984).
Other cannabinoids present in marijuana include CBD, CBC, and CBN. CBD, a major
cannabinoid of marijuana, is insoluble in water and lipid-soluble. Chemically, CBD is
2-[(1R,6R)-3-methyl-6-prop-1-en-2-ylcyclohex-2-en-1-yl]-5-pentylbenzene-1,3-diol.
CBD does not have cannabinol-like psychoactivity (Adams and Martin, 1996; Agurell
et al., 1984, 1986; Hollister, 1986). CBC is another major cannabinoid in marijuana.
Chemically, CBC is 2-methyl-2-(4-methylpent-3-enyl)-7-pentyl-5-chromenol. CBN, a
major metabolite of delta9-THC, is also a minor naturally-occurring cannabinoid with
weak psychoactivity. Chemically, CBN is 6,6,9-trimethyl-3-pentyl-benzo[c]chromen1-ol.
Different marijuana samples derived from various cultivated strains may differ in
chemical constituents including delta9-THC and other cannabinoids (Appendino et al.
2011 ). As a consequence, marijuana products from different strains may have
different safety, biological, pharmacological, and toxicological profiles. In addition to
differences between cultivated strains, the concentration of delta9-THC and other
cannabinoids in marijuana may vary with growing conditions and processing after
harvest. In addition to genetic differences among Cannabis species, the plant parts
collected—for example, flowers, leaves, and stems—can influence marijuana's
potency, quality, and purity (Adams and Martin, 1996; Agurell et al., 1984;
Mechoulam, 1973). All these variations produce marijuana with potencies, as
indicated by cannabinoid content, on average from as low as 1-2 percent to as high as
17 percent.
Overall, these variations in the concentrations of cannabinoids and other chemical
constituents in marijuana complicate the interpretation of clinical data using
marijuana. The lack of consistent concentrations of delta9 -THC and other substances
in marijuana from diverse sources makes interpreting the effect of different marijuana
constituents difficult. In addition to different cannabinoid concentrations having
different pharmacological and toxicological profiles, the non-cannabinoid components
in marijuana, such as other terpenoids and flavonoids, might also contribute to the
overall pharmacological and toxicological profiles of various marijuana strains and
products derived from those strains.
The term marijuana is often used to refer to a mixture of the dried flowering tops and
leaves from Cannabis. Marijuana in this limiting definition is one of three major
derivatives sold as separate illicit products, which also include hashish and hash oil.
According to the DEA, Cannabis saliva is the primary species of Cannabis currently
marketed illegally in the United States.
Marijuana can vary in cannabinoid content and potency (Agurell et al., 1984, 1986;
Mechoulam 1973, Cascini et al., 2012). In the usual mixture of leaves and stems
28

 distributed as marijuana, the concentration of delta9-THC averages over 12 percent by
weight. However, specially grown and selected marijuana can contain 15 percent or
greater delta9-THC (Appendino et al. 2011). Thus, a 1-gram marijuana cigarette might
contain delta9-THC in a range from as little as 3 milligrams to as much as 150
milligrams or more. Additionally, a recent systematic review and meta-analysis found
that marijuana's delta9-THC content has increased significantly from 1979-2009
(Cascini et al., 2012). In addition to smoking marijuana, individuals ingest marijuana
through food made with butter or oil infused with marijuana and its extracts. These
marijuana butters are generally made by adding marijuana to butter and heating it. The
resultant butter is then used to cook a variety of foods. There are no published studies
measuring the concentrations of cannabinoids in these marijuana food products.
Hashish consists of the dried and compressed cannabinoid-rich resinous material of
Cannabis and comes in a variety of forms (e.g. balls and cakes). Individuals may
break off pieces, place it into a pipe and smoke it. DEA reports that cannabinoid
content in hashish averages six percent (DEA, 2005). With the development and
cultivation of more high potency Cannabis strains, the average cannabinoid content in
hashish will likely increase.
Hash oil is produced by solvent extraction of the cannabinoids from plant material.
The extract's color and odor vary, depending on the solvent type used. Hash oil is a
viscous brown- or amber-colored liquid containing approximately 50 percent
cannabinoids. One or two drops of the liquid placed on a cigarette purportedly produce
the equivalent of a single· marijuana cigarette (DEA, 2005).
In conclusion, marijuana has hundreds of cultivars containing variable concentrations
of delta9-THC, cannabinoids, and other compounds. Thus, marijuana is not a single
chemical with a consistent and reproducible chemical profile or predictable and
consistent clinical effects. A guidance for industry, entitled Botanical Drug Products,8
provides information on the approval of botanical drug products. To investigate
marijuana for medical use in a manner acceptable as support for marketing approval
under an NDA, clinical studies under an IND of consistent batches of a particular
marijuana product for particular disease indications should be conducted. In addition,
information and data regarding the marijuana product's chemistry, manufacturing and
control, pharmacology, and animal toxicology data, among others must be provided
and meet the requirements for new drug approval (See 21 CFR 314.50).
Human Pharmacokinetics
Marijuana can be taken in a variety of formulations by multiple routes of
administration. Individuals smoke marijuana as a cigarette, weighing between 0.5 and
1.0 gram, or in a pipe. Additionally, individuals take marijuana orally in foods or as an
8

This guidance is available on the Internet at http://www.fda. gov/Drugs/default.htm under Guidance
(Drugs).

29

 extract in ethanol or other solvents. More recently, access to vaporizers provides
another means for abusers to inhale marijuana,
The absorption, metabolism, and pharmacokinetic profile of delta9-THC,
cannabinoids, and drug products containing delta9-THC vary with route of
administratfon and formulation (Adams and Martin, 1996; Agurell et al., 1984, 1986).
Pharmacokinetics of Smoked Administration of Cannabinoids
Characterization of the pharmacokinetics of delta9-THC and other cannabinoids from
smoked marijuana is difficult because a subject's smoking behavior during an
experiment varies (Agurell et al., 1986; Heming et al., 1986; Huestis et al., 1992a).
Each puff delivers a discrete dose of delta9-THC. An experienced marijuana smoker
can titrate and regulate the dose to obtain the desired acute psychological effects and
minimize undesired effects. For example, under naturalistic conditions, users hold
marijuana smoke in their lungs for an extended period of time which causes prolonged
absorption and increases psychoactive effects. The effect of experience in the
psychological response may explain why delta9-THC venous blood levels correlate
poorly with intensity of effects and intoxication level (Agurell et al. 1986; Barnett et
al. 1985; Huestis et al., 1992a). Puff and inhalation volumes should be recorded in
studies as the concentration (dose) of cannabinoids administered can vary at different
stages of smoking.
Smoked marijuana results in absorption of delta9-THC in the form of an aerosol within
seconds. Psychoactive effects occur immediately following absorption, with mental
and behavioral effects measurable for up to 6 hours (Grotenhermen, 2003; Hollister
1986, 1988). Delta9-THC is delivered to the brain rapidly and efficiently as expected
of a very lipid soluble drug.
The bioavailability of the delta9-THC, from marijuana in a cigarette or pipe, can range
from 1 to 24 percent with the fraction absorbed rarely exceeding 10 to 20 percent
(Agurell et al.,1986; Hollister, 1988). The relatively low and variable bioavailability
results from significant loss of delta9-THC in side-stream smoke, variation in
individual smoking behaviors, cannabinoid pyrolysis, incomplete absorption of
inhaled smoke, and metabolism in the lungs. An individual's experience and technique
with smoking marijuana also determines the dose absorbed (Heming et al., 1986;
Johansson et al., 1989). After smoking, delta9-THC venous levels decline
precipitously within minutes, and continue to go down to about 5 to 10 percent of the
peak level within an hour (Agurell et al., 1986, Huestis et al.,1992a, 1992b).
Pharmacokinetics for Oral Administration of Cannabinoids
After oral administration of delta9-THC or marijuana, the onset of effects starts within
30 to 90 minutes, reaches its peak after 2 to 3 hours and then remains for 4 to 12 hours
(Grotenhermen, 2003; Adams and Martin, 1996; Agurell et al., 1984, 1986). Due to
the delay in onset of effects, users have difficulty in titrating oral delta9-THC doses
30

 compared to smoking marijuana. Oral bioavailability of delta9-THC, whether pure or
in marijuana, is low and extremely variable, ranging between 5 and 20 percent
(Agurell et al., 1984, 1986). Following oral administration of radioactive-labeled
delta9-THC, delta9-THC plasma levels are low relative to plasma levels after smoking
or intravenous administration. Inter- and intra-subject variability occurs even with
repeated dosing under controlled conditions. The low and variable oral bioavailability
of delta9-THC is a consequence of its first-pass hepatic elimination from blood and
erratic absorption from stomach and bowel.
Cannabinoid Metabolism and Excretion
Cannabinoid metabolism is complex. Delta9-THC is metabolized via microsomal
hydroxylation to both active and inactive metabolites (Lemberger et al., 1970, 1972a,
1972b; Agurell et al., 1986; Hollister, 1988). The primary active metabolite of delta9THC following oral ingestion is 11-hydroxy-delta9-THC. This metabolite is
approximately equipotent to delta9-THC in producing marijuana-like subjective effects
(Agurell et al., 1986, Lemberger and Rubin, 1975). After oral administration,
metabolite levels may exceed that of delta9-THC and thus contribute greatly to the
pharmacological effects of oral delta9-THC or marijuana.
Plasma clearance of delta9-THC approximates hepatic blood flow at about 950 ml/min
or greater. The rapid disappearance of delta9-THC from blood is largely due to
redistribution to other tissues in the body, rather than to metabolism (Agurell et al.,
1984, 1986). Metabolism in most tissues is relatively slow or absent. Slow release of
delta9-THC and other cannabinoids from tissues and subsequent metabolism results in
a long elimination half-life. The terminal half-life of delta9-THC ranges from
approximately 20 hours to as long as 10 to 13 days, though reported estimates vary as
expected with any slowly cleared substance and the use of assays with variable
sensitivities (Hunt and Jones, 1980). Lemberger et al. (1970) determined the half-life
of delta9-THC to range from 23 to 28 hours in heavy marijuana users to 60 to 70 hours
in naive users. In addition to 11-hydroxy-delta9-THC, some inactive carboxy
metabolites have terminal half-lives of 50 hours to 6 days or more. The latter
substances serve as long-term markers in urine tests for earlier marijuana use.
The majority of the absorbed delta9-THC dose is eliminated in feces, and about 33
percent in urine. Delta9-THC enters enterohepatic circulation and undergoes
hydroxylation and oxidation to 11-nor-9-carboxy-delta9-THC. The glucuronide is
excreted as the major urine metabolite along with about 18 non-conjugated
metabolites. Frequent and infrequent marijuana users metabolize delta9-THC similarly
(Agurell et al., 1986).
Status of Research into the Medical Uses for Marijuana
State-level public initiatives, including laws and referenda in support of the medical
use of marijuana, have generated interest in the medical community and the need for
high quality clinical investigation as well as comprehensive safety and effectiveness
31

 data. In order to address the need for high quality clinical investigations, the state of
California established the Center for Medicinal Cannabis Research (CMCR,
www.cmcr.ucsd.edu) in 2000 "in response to scientific evidence for therapeutic
possibilities of cannabis9 and local legislative initiatives in favor of compassionate
use" (Grant, 2005). State legislation establishing the CMCR called for high quality
medical research that would "enhance understanding of the efficacy and adverse
effects of marijuana as a pharmacological agent," but stressed the project "should not
be construed as encouraging or sanctioning the social or recreational use of
marijuana." The CMCR funded many of the published studies on marijuana's potential
use for treating multiple sclerosis, neuropathic pain, appetite suppression and
cachexia. However, aside from the data produced by CMCR, no state-level medical
marijuana laws have produced scientific data on marijuana's safety and effectiveness.
FDA approves medical use of a drug following a submission and review of an NDA or
BLA. The FDA has not approved any drug product containing marijuana for
marketing. Even so, results of small clinical exploratory studies have been published
in the current medical literature. Many studies describe human research with
marijuana in the United States under FDA-regulated IND applications.
However, FDA approval of an NDA is not the only means through which a drug can
have a currently accepted medical use in treatment in the United States. In general, a
drug may have a "currently accepted medical use" in treatment in the United States if
the drug meets a five-part test. Established case law (Alliance for Cannabis
Therapeutics v. DEA, 15 F.3d 1131, 1135 (D.C. Cir. 1994)) upheld the Administrator
of DEA's application of the five-part test to determine whether a drug has a "currently
accepted medical use." The following describes the five elements that characterize
"currently accepted medical use" for a drug10:
i.

the drug's chemistry must be known and reproducible
"The substance's chemistry must be scientifically established to permit it
to be reproduced into dosages which can be standardized. The listing of
the substance in a current edition of one of the official compendia, as
defined by section 201 G) of the Food, Drug and Cosmetic Act, 21 U.S.C.
321G), is sufficient to meet this requirement."

ii.

there must be adequate safety studies
"There must be adequate pharmacological and toxicological studies, done
by all methods reasonably applicable, on the basis of which it could fairly
and responsibly be concluded, by experts qualified by scientific training
and experience to evaluate the safety and effectiveness of drugs, that the
substance is safe for treating a specific, recognized disorder."

9

In this quotation the term cannabis is interchangeable with marijuana.
57 FR 10499, 10504-06 (March 26, 1992).

10

32

 iii.

there must be adequate and well-controlled studies proving efficacy
"There must be adequate, well-controlled, well-designed, well-conducted,
and well-documented studies, including clinical investigations, by experts
qualified by scientific training and experience to evaluate the safety and
effectiveness of drugs, on the basis of which it could be fairly and
responsibly concluded by such experts that the substance will have the
intended effect in treating a specific, recognized disorder."

iv.

the drug must be accepted by qualified experts
"The drug has a New Drug Application (NDA) approved by the Food and
Drug Administration, pursuant to the Food, Drug and Cosmetic Act, 21
U.S.C. 355. Or, a consensus of the national community of experts,
qualified by scientific training and experience to evaluate the safety and
effectiveness of drugs, accepts the safety and effectiveness of the
substance for use in treating a specific, recognized disorder. A material
conflict of opinion among experts precludes a finding of consensus." and

v.

the scientific evidence must be widely available.
"In the absence of NDA approval, information concerning the chemistry,
pharmacology, toxicology, and effectiveness of the substance must be
reported, published, or otherwise widely available, in sufficient detail to
permit experts, qualified by scientific training and experience to evaluate
the safety and effectiveness of drugs, to fairly and responsibly conclude
the substance is safe and effective for use in treating a specific, recognized
disorder."

Marijuana does not meet any of the five elements necessary for a drug to have a
"currently accepted medical use."
Firstly, the chemistry of marijuana, as defined in the petition, is not reproducible in
terms of creating a standardized dose. The petition defines marijuana as including all
Cannabis cultivated strains. Different marijuana samples derived from various
cultivated strains may have very different chemical constituents including delta9-THC
and other cannabinoids (Appendino et al., 2011). As a consequence, marijuana
products from different strains will have different safety, biological, pharmacological,
and toxicological profiles. Thus, when considering all Cannabis strains together,
because of the varying chemical constituents, reproducing consistent standardized
doses is not possible. Additionally, smoking marijuana currently has not been shown
to allow delivery of consistent and reproducible doses. However, if a specific
Cannabis strain is grown and processed under strictly controlled conditions, the plant
chemistry may be kept consistent enough to produce reproducible and standardized
doses.
33

 As to the second and third criteria; there are neither adequate safety studies nor
adequate and well-controlled studies proving marijuana's efficacy. To support the
petitioners' assertion that marijuana has accepted medical use, the petitioners cite the
American Medical Association's (AMA) 2009 report entitled "Use of Cannabis for
Medicinal Purposes." The petitioners claim the AMA report is evidence the AMA
accepts marijuana's safety and efficacy. However, the 2009 AMA report clarifies that
the report "should not be viewed as an endorsement of state-based medical cannabis
programs, the legalization of marijuana, or that scientific evidence on the therapeutic
use of cannabis meets the same and current standards for a prescription drug
product."11
Currently, no published studies conducted with marijuana meet the criteria of an
adequate and well-controlled efficacy study. The criteria for an adequate and wellcontrolled study for purposes of determining the safety and efficacy of a human drug
are defined under the Code of Federal Regulations (CFR) in 21 CFR 314.126. In order
to assess this element, FDA conducted a review of clinical studies published and
available in the public domain before February, 2013. Studies were identified through
a search of PubMed12 for articles published from inception to February 2013, for
randomized controlled trials using marijuana to assess marijuana's efficacy in any
therapeutic indication. Additionally, the review included studies identified through a
search of bibliographic references in relevant systematic reviews and identified studies
presenting original research in any language. Selected studies needed to be placebocontrolled and double-blinded. Additionally, studies needed to encompass
administered marijuana plant material. There was no requirement for any specific
route of administration, nor any age limits on study subjects. Studies were excluded
that used placebo marijuana supplemented by the addition of specific amounts of THC
or other cannabinoids. Additionally, studies administering marijuana plant extracts
were excluded.
The PubMed search yielded a total of 566 abstracts of scientific articles. Of these
abstracts, a full-text review was conducted with 85 papers to assess eligibility. Of the
studies identified through the search of the references and the 566 abstracts from the
PubMed search, only 11 studies met all the criteria for selection (Abrams et al., 2007;
Corey-Bloom et al., 2012; Crawford and Merritt, 1979; Ellis et al., 2009; Haney et al.,
2005; Haney et al., 2007; Merritt et al., 1980; Tashkin et al., 1974; Ware et al., 2010;
Wilsey et al., 2008; Wilsey et al., 2013). These 11 studies were published between
1974 and 2013. Ten of these studies were conducted in the United States and one
study was conducted in Canada. The identified studies examine the effects of smoked
and vaporized marijuana for the indications of chronic neuropathic pain, spasticity
related to Multiple Sclerosis (MS), appetite stimulation in human immunodeficiency
virus (HIV) patients, glaucoma, and asthma. All studies used adult subjects.
11

In this quotation the term cannabis is used interchangeably for marijuana.
The following search strategy was used, "(cannabis OR marijuana) AND (therapeutic use OR therapy)
AND (RCT OR randomized controlled trial OR "systematic review" OR clinical trial OR clinical trials)
NOT ("marijuana abuse"[Mesh] OR addictive behavior OR substance related disorders)."
12

34

 The 11 identified studies were individually evaluated to determine if they successfully
meet accepted scientific standards. Specifically, they were evaluated on study design
including subject selection criteria, sample size, blinding techniques, dosing
paradigms, outcome measures, and the statistical analysis of the results. The analysis
relied on published studies, thus information available about protocols, procedures,
and results were limited to documents published and widely available in the public
domain. The review found that all 11 studies that examined effects of inhaled
marijuana do not currently prove efficacy of marijuana in any therapeutic indication
based on a number of limitations in their study design; however, they may be
considered proof of concept studies. Proof of concept studies provide preliminary
evidence on a proposed hypothesis involving a drug's effect. For drugs under
development, the effect often relates to a short-term clinical outcome being
investigated. Proof of concept studies often serve as the link between preclinical
studies and dose ranging clinical studies. Thus, proof of concept studies generally are
not sufficient to prove efficacy of a drug because they provide only preliminary
information about the effects of a drug.
In addition to the lack of published adequate and well-controlled efficacy studies
proving efficacy, the criteria for adequate safety studies has also not been met.
Importantly, in its discussion of the five-part test used to determine whether a drug has
a "currently accepted medical use," DEA said, "No drug can be considered safe in the
abstract. Safety has meaning only when judged against the intended use of the drug, its
known effectiveness, its known and potential risks, the severity of the illness to be
treated, and the availability of alternative remedies" (57 FR 10504). When
determining whether a drug product is safe and effective for any indication, FDA
performs an extensive risk-benefit analysis to determine whether the risks posed by
the drug product's side effects are outweighed by the drug product's potential benefits
for a particular indication. Thus, contrary to the petitioner's assertion that marijuana
has accepted safety, in the absence of an accepted therapeutic indication which can be
weighed against marijuana's risks, marijuana does not satisfy the element for having
adequate safety studies such that experts may conclude that it is safe for treating a
specific, recognized disorder.
The fourth of the five elements for determining "currently accepted medical use"
requires that the national community of experts, qualified by scientific training and
experience to evaluate the safety and effectiveness of drugs, accepts the safety and
effectiveness of the substance for use in treating a specific, recognized disorder. A
material conflict of opinion among experts precludes a finding of consensus. Medical
practitioners who are not experts in evaluating drugs are not qualified to determine
whether a drug is generally recognized as safe and effective or meets NDA
requirements (57 FR 10499-10505).
There is no evidence that there is a consensus among qualified experts that marijuana
is safe and effective for use in treating a specific, recognized disorder. As discussed
above, there are not adequate scientific studies that show marijuana is safe and
35

 effective in treating a specific, recognized disorder. In addition, there is no evidence
that a consensus of qualified experts have accepted the safety and effectiveness of
marijuana for use in treating a specific, recognized disorder. Although medical
practitioners are not qualified by scientific training and experience to evaluate the
safety and effectiveness of drugs, we also note that the AMA's report, entitled "Use of
Cannabis for Medicinal Purposes," does not accept that marijuana currently has
accepted medical use. Furthermore, based on the above definition of a "qualified
expert", who is an individual qualified by scientific training and experience to evaluate
the safety and effectiveness of a drug, state-level medical marijuana laws do not
provide evidence of a consensus among qualified experts that marijuana is safe and
effective for use in treating a specific, recognized disorder.
As to the fifth part of the test, which requires that information concerning the
chemistry, pharmacology, toxicology, and effectiveness of marijuana to be reported in
sufficient detail, the scientific evidence regarding all of these aspects is not available
in sufficient detail to allow adequate scientific scrutiny. Specifically, the scientific
evidence regarding marijuana's chemistry in terms of a specific Cannabis strain that
could produce standardized and reproducible doses is not currently available.
Alternately, a drug can be considered to have a "currently accepted medical use with
severe restrictions" (21 U.S.C. 812(b)(2)(B)), as allowed under the stipulations for a
Schedule II drug. Yet, as stated above, currently marijuana does not have any accepted
medical use, even under conditions where its use is severely restricted.
In conclusion, to date, research on marijuana's medical use has not progressed to the
point where marijuana is considered to have a "currently accepted medical use" or a
"currently accepted medical use with severe restrictions."

4. ITS HISTORY AND CURRENT PATTERN OF ABUSE
Under the fourth factor, the Secretary must consider the history and current pattern of
marijuana abuse. A variety of sources provide data necessary to assess abuse patterns
and trends of marijuana. The data indicators of marijuana use include the NSDUH,
MTF, DAWN, and TEDS. The following briefly describes each data source, and
summarizes the data from each source.
National Survey on Drug Use and Health (NSDUH)13

13

NSDUH provides national estimates of the prevalence and incidence of illicit drug, alcohol and tobacco
use in the United States. NSDUH is an annual study conducted by SAMHSA. Prior to 2002, the database
was known as the National Household Survey on Drug Abuse (NHSDA). NSDUH utilizes a nationally
representative sample of United States civilian, non-institutionalized population aged 12 years and older.
The survey excludes homeless people who do not use shelters, active military personnel, and residents of
institutional group quarters such as jails and hospitals. The survey identifies whether an individual used a
drug within a specific time period, but does not identify the amount of the drug used on each occasion.
NSDUH defines "current use" as having used the substance within the month prior to the study.

36

 According to 2012 NSDUH14 data, the most recent year with complete data, the use of
illicit drugs, including marijuana, is increasing. The 2012 NSDUH estimates that 23.9
million individuals over 12 years of age (9.2 percent of the U.S. population) currently
use illicit drugs, which is an increase of 4.8 million individuals from 2004 when 19.1
million individuals (7.9 percent of the U.S. population) were current illicit drug users.
NSDUH reports marijuana as the most commonly used illicit drug, with 18.9 million
individuals (7.3 percent of the U.S. population) currently using marijuana in 2012.
This represents an increase of 4.3 million individuals from 2004, when 14.6 million
individuals (6.1 percent of the U.S. population) were current marijuana users.
The majority of individuals who try marijuana at least once in their lifetime do not
currently use marijuana. The 2012 NSDUH estimates that 111.2 million individuals
(42.8 percent of the U.S. population) have used marijuana at least once in their
lifetime. Based on this estimate and the estimate for the number of individuals
currently using marijuana, approximately 16.9 percent of those who have tried
marijuana at least once in their lifetime currently use marijuana; conversely, 83.1
percent do not currently use marijuana. In terms of the frequency of marijuana use, an
estimated 40.3 percent of individuals who used marijuana in the past month used
marijuana on 20 or more days within the past month. This amount corresponds to an
estimated 7.6 million individuals who used marijuana on a daily or almost daily basis.
Some characteristics of marijuana users are related to age, gender, and criminal justice
system involvement. In observing use among different age cohorts, the majority of
individuals who currently use marijuana are shown to be between the ages of 18-25,
with 18.7 percent of this age group currently using marijuana. In the 26 and older age
group, 5.3 percent of individuals currently use marijuana. Additionally, in individuals
aged 12 years and older, males reported more current marijuana use than females.
NSDUH includes a series of questions aimed at assessing the prevalence of
dependence and abuse of different substances in the past 12 months.15 In 2012,
marijuana was the most common illicit drug reported by individuals with past year
dependence or abuse. An estimated 4.3 million individuals meet the NSDUH criteria
for marijuana dependence or abuse in 2012. The estimated rates and number of
individuals with marijuana dependence or abuse has remained similar from 2002 to
2012. In addition to data on dependence and abuse, NSDUH includes questions aimed
14

2013; http: //www.samhsa.gov/data/NSDUH.aspx
"These questions are used to classify persons as dependent on or abusing specific substances based on
criteria specified in the Diagnostic and Statistical Manual of Mental Disorder, 4th edition (DSM-IV). The
questions related to dependence ask about health and emotional problems associated with substance use,
unsuccessful attempts to cut down on use, tolerance, withdrawal, reducing other activities to use
substances, spending a lot time engaging in activities related to substance use, or using the substance in
greater quantities or for longer time than intended. The questions on abuse ask about problems at work,
home, and school; problems with family or friends; physical danger; and trouble with the law due to
substance use. Dependence is considered to be a more severe substance use problem than abuse because it
involves the psychological and physiological effects of tolerance and withdrawal." (NSDUH,
2013).
15

37

 at assessing treatment for a substance use problem.16 In 2012, an estimated 957,000
persons received treatment for marijuana use during their most recent treatment in the
year prior to the survey.
Monitoring the Future (MTF)17
According to MTF18, rates of marijuana and illicit drug use declined for all three
grades from 2005 through 2007. However, starting around 2008, rates of annual use of
illicit drugs and marijuana increased through 2013 for all three grades. Marijuana
remained the most widely used illicit drug during all time periods. The prevalence of
annual and past month marijuana use in 10th and 12th graders in 2013 is greater than in
2005. Table 1 lists the lifetime, annual, and monthly prevalence rates of various drugs
for 8th, 10th, and 12th graders in 2013.
Table 1: Trends in lifetime, annual, and monthly prevalence of use of various drugs
for eighth, tenth, and twelfth graders. Percentages represent students in survey
responding that they had used a drug at least once in their lifetime, in the past year,
or in the past 30 days.

Any illicit Drug (a)
8th Grade
10th Grade
12th Grade
Marijuana/Hashish
8th Grade
10th Grade
12th Grade

Lifetime
2011 2012 2013

Annual
2011 2012 2013

30-Day
2011 2012 2013

20.1
37.7
49.9

18.5
36.8
49.1

20.3
38.8
50.4

14.7
31.1
40.0

13.4
30.1
39.7

14.9
31.8
40.3

8.5
19.2
25.2

7.7
18.6
25.2

8.5
19.4
25.5

16.4
34.5
45.5

15.2
33.8
45.2

16.5
35.8
45.5

12.5
28.8
36.4

11.4
28.0
36.4

12.7
29.8
36.4

7.2
17.6
22.6

6.5
17.0
22.9

7.0
18.0
22.7

SOURCE: The Monitoring the Future Study, the University of Michigan
a. For 12th graders only: "any illicit drug" includes any use of marijuana, LSD, other
hallucinogens, crack, other cocaine, or heroin; or any narcotics use other than heroin,
amphetamines, sedatives (barbiturates), or tranquilizers not under a doctor's orders. For

16

"Estimates ... refer to treatment received for illicit drug or alcohol use, or for medical problems
associated with the use of illicit drugs or alcohol. This includes treatment received in the past year at any
location, such as a hospital (inpatient), rehabilitation facility (outpatient or inpatient), mental health center,
emergency room, private doctor's office, prison or jail, or a self-help group, such as Alcoholics Anonymous
or Narcotics Anonymous." (NSDUH, 2013).
17
Monitoring the Future is a national survey that tracks drug use prevalence and trends among adolescents
in the United States. MTF is reported annually by the Institute for Social Research at the University of
Michigan under a grant from NIDA. Every spring, MTF surveys 8 th, 10th, and 12th graders in randomly
selected U.S. schools. MTF has been conducted since 1975 for 12 th graders and since 1991 for 8th and 10th
graders. The MTF survey presents data in terms of prevalence among the sample interviewed. For 2012, the
latest year with complete data, the sample sizes were 15,200 - 8th graders; 13,300 – 10th graders; and 13,200
- 12th graders. In all, a total of about 41,700 students of 389 schools participated in the 2013 MTF.
18
2013; http: //www.monitoringthefuture.org/index.html

38

 8th and 10th graders only: the use of narcotics other than heroin and sedatives
(barbiturates) was excluded.

Drug Abuse Warning Network (DAWN)19
Importantly, many factors can influence the estimates of ED visits, including trends in
overall use of a substance as well as trends in the reasons for ED usage. For instance,
some drug users may visit EDs for life-threatening issues while others may visit to
seek care for detoxification because they needed certification before entering
treatment. Additionally, DAWN data do not distinguish the drug responsible for the
ED visit from other drugs that may have been used concomitantly. As stated in a
DAWN report, "Since marijuana/hashish is frequently present in combination with
other drugs, the reason for the ED visit may be more relevant to the other drug(s)
involved in the episode."
For 2011, DAWN20 estimates a total of 5,067,374 (95 percent confidence interval [CI]:
4,616,753 to 5,517,995) drug-related ED visits from the entire United States. Of these,
approximately 2,462,948 ([CI]: 2,112,868 to 2,813,028) visits involved drug misuse or
abuse.
During the same period, DAWN estimates that 1,252,500 (CI: 976, 169 to 1,528,831)
drug related ED visits involved illicit drugs. Thus, over half of all drug-related ED
visits associated with drug misuse or abuse involved an illicit drug. For ED visits
involving illicit drugs, 56.3 percent involved multiple drugs while 43.7 percent
involved a single drug.
Marijuana was involved in 455,668 ED visits (CI: 370,995 to 540,340), while cocaine
was involved in 505,224 (CI: 324,262 to 686, 185) ED visits, heroin was involved in
258,482 (CI: 205,046 to 311,918) ED visits and stimulants including amphetamine
and methamphetamine were involved in 159,840 (CI: 100,199 to 219,481) ED visits.
Other illicit drugs, such as PCP, MDMA, GHB and LSD were much less frequently
associated with ED visits. The number of ED visits involving marijuana has increased
by 62 percent since 2004.
Marijuana-related ED visits were most frequent among young adults and minors.
Individuals under the age of 18 accounted for 13.2 percent of these marijuana-related
visits, whereas this age group accounted for approximately 1.2 percent of ED visits
19

DAWN is a national probability survey of the U.S. hospitals with ED designed to obtain information on
drug related ED visits. DAWN is sponsored by SAMHSA. The DAWN system provides information on the
health consequences of drug use in the United States, as manifested by drug-related visits to ED. The ED
data from a representative sample of hospital emergency departments are weighted to produce national
estimates. Importantly, DAWN data and estimates, starting in 2004, are not comparable to those for prior
years because of vast changes in the methodology used to collect the data. Furthermore, estimates for 2004
are the first to be based on a redesigned sample of hospitals, which ended in 2011.
20
2011; http: //www.samhsa.gov/data/dawn.aspx

39

 involving cocaine, and less than 1 percent of ED visits involving heroin. However, the
age group with the most marijuana-related ED visits was between 25 and 29 years old.
Yet, because populations differ between age groups, a standardized measure for
population size is useful to make comparisons. For marijuana, the rates of ED visits
per 100,000 population were highest for patients aged 18 to 20 (443.8 ED visits per
100,000) and for patients aged 21 to 24 (446.9 ED visits per 100,000).
While DAWN provides estimates for ED visits associated with the use of medical
marijuana for 2009-2011, the validity of these estimates is questionable. Because the
drug is not approved by the FDA, reporting medical marijuana may be inconsistent
and reliant on a number of factors including whether the patient self-reports the
marijuana use as medicinal, how the treating health care provider records the
marijuana use, and lastly how the SAMHSA coder interprets the report. All of these
aspects will vary greatly between states with medical marijuana laws and states
without medical marijuana laws. Thus, even though estimates are reported for medical
marijuana related ED visits, medical marijuana estimates cannot be assessed with any
acceptable accuracy at this time, as FDA has not approved marijuana treatment of any
medical condition. These data show the difficulty in evaluating abuse of a product that
is not currently approved by FDA, but authorized for medical use, albeit
inconsistently, at the state level. Thus, we believe the likelihood of the treating health
care provider or SAMHSA coder attributing the ED visit to "medical marijuana"
versus "marijuana" to be very low. Overall, the available data are inadequate to
characterize its abuse at the community level.
Treatment Episode Data Set (TEDS)21
Primary marijuana abuse accounted for 18.1 percent of all 2011 TEDS22 admissions.
Individuals admitted for primary marijuana abuse were nearly three-quarters (73.4
percent) male, and almost half (45.2 percent) were white. The average age at
admission was 24 years old, and 31.1 percent of individuals admitted for primary
marijuana abuse were under the age of 18. The reported frequency of marijuana use
was 24.3 percent reporting daily use. Almost all (96.8 percent) primary marijuana

21

The TEDS system is part of SAMHSA's Drug and Alcohol Services Information System (Office of
Applied Science, SAMHSA). The TEDS report presents information on the demographic and substance use
characteristics of the 1.8 million annual admissions to treatment for alcohol and drug abuse in facilities that
report to individual state administrative data systems. Specifically, TEDS includes facilities licensed or
certified by the states to provide substance abuse treatment and is required by the states to provide TEDS
client-level data. Facilities that report TEDS data are those receiving State alcohol and drug agency funds
for the provision of alcohol and drug treatment services. Since TEDS is based only on reports from these
facilities, TEDS data do not represent the total national demand for substance abuse treatment or the
prevalence of substance abuse in the general population. The primary goal for TEDS is to monitor the
characteristics of treatment .episodes for substance abusers. Importantly, TEDS is an admissions-based
system, where admittance to treatment is counted as an anonymous tally. For instance, a given individual
who is admitted to treatment twice within a given year would be counted as two admissions. The most
recent year with complete data is 2011.
22
2011; http://www.samhsa.gov/data/DASIS.aspx?qr=t#TEDS

40

 users utilized the substance by smoking. Additionally, 92.9 percent reported using
marijuana for the first time before the age of 18.
An important aspect of TEDS admission data for marijuana is of the referral source for
treatment. Specifically, primary marijuana admissions were less likely than all other
admissions to either be self-referred or referred by an individual for treatment. Instead,
the criminal justice system referred more than half (51.6 percent) of primary marijuana
admissions.
Since 2003, the percent of admissions for primary marijuana abuse increased from
15.5 percent of all admissions in 2003 to 18.l percent in 2011. This increase is less
than the increase seen for admissions for primary opioids other than heroin, which
increased from 2.8 percent in 2003 to 7.3 percent in 2011. In contrast, the admissions
for primary cocaine abuse declined from 9.8 percent in 2003 to 2.0 percent in 2011.

5. THE SCOPE, DURATION, AND SIGNIFICANCE OF ABUSE
Under the fifth factor, the Secretary must consider the scope, duration, and
significance of marijuana abuse. According to 2012 data from NSDUH and 2013 data
from MTF, marijuana remains the most extensively used illegal drug in the United
States, with 42.8 percent of U.S. individuals over age 12 (111.2 million) and 45.5
percent of 12th graders having used marijuana at least once in their lifetime. Although
the majority of individuals over age 12 (83.1 percent) who have ever used marijuana
in their lifetime do not use the drug monthly, 18.9 million individuals (7.3 percent of
the U.S. population) report that they used marijuana within the past 30 days. An
examination of use among various age cohorts through NSDUH demonstrates that
monthly use occurs primarily among college-aged individuals, with use dropping off
sharply after age 25. Additionally, NSDUH data show the number of individuals
reporting past-month use of marijuana has increased by 4.3 million individuals since
2004. Data from MTF shows that annual prevalence of marijuana use declined for all
three grades from 2005 through 2007, then began to rise through 2013. Additionally,
in 2013, 1.1 percent of 8th graders, 4.0 percent of 10th graders, and 6.5 percent of 12th
graders reported daily use of marijuana, defined as use on 20 or more days within the
past 30 days.
The 2011 DAWN data show that marijuana use was mentioned in 455,668 ED visits,
which amounts to approximately 36.4 percent of all illicit drug-related ED visits.23

23

Many factors can influence the estimates of ED visits, including trends in the reasons for ED usage. For
instance, some drug users may visit EDs for life-threatening issues while others may visit to seek care for
detoxification because they needed certification before entering treatment. Additionally, DAWN data do
not distinguish the drug responsible for the ED visit from other drugs that may have been used
concomitantly. As stated in a DAWN report, "Since marijuana/hashish is frequently present in combination
with other drugs, the reason for the ED visit may be more relevant to the other drug(s) involved in the
episode."

41

 TEDS data for 2011 show that 18.1 percent of all admissions were for primary
marijuana abuse.24 Between 2003 and 2011, there was a 2.6 percent increase in the
number of TEDS admissions for primary marijuana use. Approximately 61.5 percent
of primary marijuana admissions in 2011 were for individuals under the age of 25
years.

6. WHAT, IF ANY, RISK THERE IS TO THE PUBLIC HEALTH
Under the sixth factor, the Secretary must consider the risks posed to the public health
by marijuana. Factors 1, 4, and 5 include a. discussion of the risk to the public health
as measured by emergency room episodes and drug treatment admissions.
Additionally, Factor 2 includes a discussion of marijuana's central nervous system,
cognitive, cardiovascular, autonomic, respiratory, and immune system effects. Factor
6 focuses on the health risks to the individual user in terms of the risks from acute and
chronic use of marijuana, as well as the "gateway hypothesis."
Risks from Acute Use of Marijuana
Acute use of marijuana impairs psychomotor performance, including complex task
performance, which makes operating motor vehicles or heavy equipment after using
marijuana inadvisable (Ramaekers et al., 2004; Ramaekers et al., 2006a). A metaanalysis conducted by Li et al. (2011) showed an association between marijuana use
by the driver and a significantly increased risk of involvement in a car accident.
Additionally, in a minority of individuals who use marijuana, some potential responses
include dysphoria and psychological distress, including prolonged anxiety reactions
(Haney et al., 1999).
Risks from Chronic Use of Marijuana
A distinctive marijuana withdrawal syndrome following long term or chronic use has
been identified. The withdrawal syndrome indicates that marijuana produces physical
dependence that is mild, short-lived, and comparable to tobacco withdrawal (Budney
et al., 2008). Marijuana withdrawal syndrome is described in detail below under
Factor 7.
The following states how the DSM-V (2013) of the American Psychiatric Association
describes the consequences of Cannabis25 abuse:
Individuals with cannabis use disorder may use cannabis throughout the day over
a period of months or years, and thus may spend many hours a day under the
24

An important aspect of TEDS admission data for marijuana is of the referral source for treatment.
Specifically, primary marijuana admissions were less likely than all other admissions to either be selfreferred or referred by an individual for treatment. Instead, the criminal justice system referred more than
half (51.6 percent) of primary marijuana admissions.
25
Cannabis is the term used in the DSM-V to refer to marijuana. In the following excerpt the term
Cannabis is interchangeable for the term marijuana.

42

 influence. Others may use less frequently, but their use causes recurrent problems
related to family, school, work, or other important activities (e.g., repeated
absences at work; neglect of family obligations). Periodic cannabis use and
intoxication can negatively affect behavioral and cognitive functioning and thus
interfere with optimal performance at work or school, or place the individual at
increased physical risk when performing activities that could be physically
hazardous (e.g:, driving a car; playing certain sports; performing manual work
activities, including operating machinery). Arguments with spouses or parents
over the use of cannabis in the home, or its use in the presence of children, can
adversely impact family functioning and are common features of those with
cannabis use disorder. Last, individuals with cannabis use disorder may continue
using marijuana despite knowledge of physical problems (e.g., chronic cough
related to smoking) or psychological problems (e.g., excessive sedation or
exacerbation of other mental health problems) associated with its use.
Marijuana as a "Gateway Drug"
Kandel (1975) proposed nearly 40 years ago the hypothesis that marijuana is a
"gateway drug" that leads to the use or abuse of other illicit drugs. Since that time,
epidemiological research explored this premise. Overall, research does not support a
direct causal relationship between regular marijuana use and other illicit drug use.
The studies examining the gateway hypothesis are limited. First, in general, studies
recruit individuals influenced by a myriad of social, biological, and economic factors
that contribute to extensive drug abuse (Hall & Lynskey, 2005). Second, most studies
that test the hypothesis that marijuana use causes abuse of illicit drugs use the
determinative measure any use of an illicit drug, rather than DSM-5 criteria for drug
abuse or dependence on an illicit drug (DSM-5, 2013). Consequently, although an
individual who used marijuana may try other illicit drugs, the individual may not
regularly use drugs, or have a diagnosis of drug abuse or dependence.
Little evidence supports the hypothesis that initiation of marijuana use leads to an
abuse disorder with other illicit substances. For example, one longitudinal study of
708 adolescents demonstrated that early onset marijuana use did not lead to
problematic drug use (Kandel & Chen, 2000). Similarly, Nace et al. (1975) examined
Vietnam-era soldiers who extensively abused marijuana and heroin while they were in
the military, and found a lack of correlation of a causal relationship demonstrating
marijuana use leading to heroin addiction. Additionally, in another longitudinal study
of 2,446 adolescents, marijuana dependence was uncommon but when it did occur, the
common predictors of marijuana dependence were the following: parental death,
deprived socio-economic status, and baseline illicit drug use other than marijuana (von
Sydow et al., 2002).
When examining the association between marijuana and illicit drugs, focusing on drug
use versus abuse or dependence, different patterns emerge. For example, a study
examining the possible causal relationship of the gateway hypothesis found a
correlation between marijuana use in adolescents and other illicit drug use in early
43

 adulthood and, adjusting for age-linked experiences, did not effect this correlation
(Van Gundy and Rebellon, 2010). However, when examining the association in terms
of development of drug abuse; age-linked stressors and social roles moderated the
correlation between marijuana use in adolescents and other illicit drug abuse.
Similarly, Degenhardt et al. (2009) examined the development of drug dependence
and found an association that did not support the gateway hypothesis. Specifically,
drug dependence was significantly associated with the use of other illicit drugs prior to
marijuana use.
Interestingly, the order of initiation of drug use seems to depend on the prevalence of
use of each drug, which varies by country. Based on the World Health Organization
(WHO) World Mental Health Survey that includes data from 17 different countries,
the order of drug use initiation varies by country and relates to prevalence of drug use
in each country (Degenhardt et al., 2010). Specifically, in the countries with the
lowest prevalence of marijuana use, use of other illicit drugs before marijuana was
common. This sequence of initiation is less common in countries with higher
prevalence of marijuana use. A study of 9,282 households in the United States found
that marijuana use often preceded the use of other illicit drugs; however, prior nonmarijuana drug dependence was also frequently correlated with higher levels of illicit
drug abuse (Degenhardt et al., 2009). Additionally, in a large 25-year longitudinal
study of 1,256 New Zealand children, the author concluded that marijuana use
correlated to an increased risk of abuse of other drugs, including cocaine and heroin
(Fergusson et al., 2005).
Although many individuals with a drug abuse disorder may have used marijuana as
one of their first illicit drugs, this fact does not correctly lead to the reverse inference
that most individuals who used marijuana will inherently go on to try or become
regular users of other illicit drugs. Specifically, data from the 2011 NSDUH survey
illustrates this issue (SAMHSA, 2012). NSDUH data estimates 107.8 million
individuals have a lifetime history of marijuana use, which indicates use on at least
one occasion, compared to approximately 36 million individuals having a lifetime
history of cocaine use and approximately 4 million individuals having a lifetime
history of heroin use. NSDUH data do not provide information about each individual’s
specific drug history. However, even if one posits that every cocaine and heroin user
previously used marijuana, the NSDUH data show that marijuana use at least once in a
lifetime does not predict that an individual will also use another illicit drug at least
once.
Finally, a review of the gateway hypothesis by Vanyukov et al. (2012) notes that
because the gateway hypothesis only addresses the order of drug use initiation, the
gateway hypothesis does not specify any mechanistic connections between drug
"stages" following exposure to marijuana and does not extend to the risks for
addiction. This concept contrasts with the concept of a common liability to addiction
that involves mechanisms and biobehavioral characteristics pertaining to the entire
course of drug abuse risk and disorders.
44

 7. ITS PSYCHIC OR PHYSIOLOGIC DEPENDENCE LIABILITY
Under the seventh factor, the Secretary must consider marijuana's psychic or
physiological dependence liability.
Psychic or psychological dependence has been shown in response to marijuana's
psychoactive effects. Psychoactive responses to marijuana are pleasurable to many
humans and are associated with drug-seeking and drug-taking (Maldonado, 2002).
Moreover, high levels of psychoactive effects, notably positive reinforcement, are
associated with increased marijuana use, abuse, and dependence (Scherrer et al., 2009;
Zeiger et al., 2010). Epidemiological data support these findings through 2012
NSDUH statistics that show that of individuals years 12 or older who used marijuana
in the past month, an estimated 40.3 percent used marijuana on 20 or more days within
the past month. This equates to approximately 7.6 million individuals aged 12 or older
who used marijuana on a daily or almost daily basis. Additionally, the 2013 MTF data
report the prevalence of daily marijuana use, defined as use on 20 or more days within
the past 30 days, in 8th, 10th, and 12th graders is 1.1 percent, 4.0 percent, and 6.5
percent, respectively.
Tolerance is a state of adaptation where exposure to a drug induces changes that result
in a diminution of one or more of the drug's effects over time (American Academy of
Pain Medicine, American Pain Society and American Society of Addiction Medicine
consensus document, 2001). Tolerance can develop to some, but not all, of marijuana's
effects. Specifically, tolerance does not seem to develop in response to many of
marijuana's psychoactive effects. This lack of tolerance may relate to
electrophysiological data demonstrating that chronic delta9-THC administration does
not affect increased neuronal firing in the ventral tegmental area, a region known to
play a critical role in drug reinforcement and reward (Wu and French, 2000). In the
absence of other abuse indicators, such as rewarding properties, the presence of
tolerance or physical dependence does not determine whether a drug has abuse
potential.
However, humans can develop tolerance to marijuana's cardiovascular, autonomic,
and behavioral effects (Jones et al., 1981). Tolerance to some of marijuana's
behavioral effects seems to develop after heavy marijuana use, but not after occasional
marijuana use. For instance, following acute administration of marijuana, heavy
marijuana users did not exhibit impairments in tracking and attention tasks, as were
seen in occasional marijuana users (Ramaekers et al., 2009). Furthermore, a
neurophysiological assessment administered through an electroencephalograph (EEG)
which measures event-related potentials (ERP) conducted in the same subjects as the
previous study, found a corresponding effect in the P10026 component of ERPs.
Specifically, corresponding to performance on tracking and attention tasks, heavy
marijuana users showed no changes in P100 amplitudes following acute marijuana
26

The P100 component of ERPs is thought to relate to the visual processing of stimuli and can be
modulated by attention.

45

 administration, although occasional users showed a decrease in Pl00 amplitudes
(Theunissen et al., 2012). A possible mechanism underlying tolerance to marijuana's
effects may be the down-regulation of cannabinoid receptors (Hirvonen et al., 2012;
Gonzalez et al., 2005; Rodriguez de Fonseca et al., 1994; Oviedo et al., 1993).
Importantly, pharmacological tolerance alone does not indicate a drug's physical
dependence liability. In order for physical dependence to exist, evidence of a
withdrawal syndrome is needed. Physical dependence is a state of adaptation,
manifested by a drug-class specific withdrawal syndrome produced by abrupt
cessation, rapid dose reduction, decreasing blood level of the drug, and/or
administration of an antagonist (ibid). Many medications not associated with abuse or
addiction can produce physical dependence and withdrawal symptoms after chronic
use.
Discontinuation of heavy, chronic marijuana use has been shown to lead to physical
dependence and withdrawal symptoms (American Psychiatric Association DSM-V,
2013; Budney and Hughes, 2006; Haney et al., 1999). In heavy, chronic marijuana
users, the most commonly reported withdrawal symptoms are sleep difficulties,
decreased appetite or weight loss, irritability, anger, anxiety or nervousness, and
restlessness. Some less commonly reported withdrawal symptoms are depressed
mood, sweating, shakiness, physical discomfort, and chills (Budney and Hughes,
2006; Haney et al., 1999). The occurrence of marijuana withdrawal symptoms in light
or non-daily marijuana users has not been established. The American Psychiatric
Association's DSM-V (2013) includes a list of symptoms of "cannabis withdrawal."
Most marijuana withdrawal symptoms begin within 24-48 hours of discontinuation,
peak within 4-6 days, and last for 1-3 weeks. Marijuana withdrawal syndrome has
been reported in adolescents and adults admitted for substance abuse treatment.
Based on clinical descriptions, this syndrome appears to be mild compared to classical
alcohol and barbiturate withdrawal syndromes, which can include more serious
symptoms such as agitation, paranoia, and seizures. Multiple studies comparing
marijuana and tobacco withdrawal symptoms in humans demonstrate that the
magnitude and time course of the two withdrawal syndromes are similar (Budney et
al., 2008; Vandrey et al., 2005, 2008).

8. WHETHER THE SUBSTANCE IS AN IMMEDIATE PRECURSOR OF A
SUBSTANCE ALREADY CONTROLLED UNDER THIS ARTICLE
Under the eight factor analysis, the Secretary must consider whether marijuana is an
immediate precursor of a controlled substance. Marijuana is not an immediate
precursor of another controlled substance.

RECOMMENDATION

46

 After consideration of the eight factors discussed above, FDA recommends that
marijuana remain in Schedule I of the CSA. NIDA concurs with this scheduling
recommendation. Marijuana meets the three criteria for placing a substance in Schedule I
of the CSA under 21 U.S.C. 812(b)(l):
1) Marijuana has a high potential for abuse:
A number of factors indicate marijuana's high abuse potential, including the large
number of individuals regularly using marijuana, marijuana's widespread use, and the
vast amount of marijuana available for illicit use. Approximately 18.9 million
individuals in the United States (7.3 percent of the U.S. population) used marijuana
monthly in 2012. Additionally, approximately 4.3 million individuals met diagnostic
criteria for marijuana dependence or abuse in the year prior to the 2012 NSDUH
survey. A 2013 survey indicates that by 12th grade, 36.4 percent of students report
using marijuana within the past year, and 22.7 percent report using marijuana monthly.
In 2011, 455,668 ED visits were marijuana-related, representing 36.4 percent of all
illicit drug-related episodes. Primary marijuana use accounted for 18.1 percent of
admissions to drug treatment programs in 2011. Additionally, marijuana has dosedependent reinforcing effects, as demonstrated by data showing that humans prefer
relatively higher doses to lower doses. Furthermore, marijuana use can result in
psychological dependence.
2) Marijuana has no currently accepted medical use in treatment in the United
States:
FDA has not approved a marketing application for a marijuana drug product for any
indication. The opportunity for scientists to conduct clinical research with marijuana
exists, and there are active INDs for marijuana; however, marijuana does not have a
currently accepted medical use for treatment in the United States, nor does marijuana
have an accepted medical use with severe restrictions.
A drug has a "currently accepted medical use" if all of the following five elements
have been satisfied:
a. the drug's chemistry is known and reproducible;
b. there are adequate safety studies;
c. there are adequate and well-controlled studies proving efficacy;
d. the drug is accepted by qualified experts; and
e. the scientific evidence is widely available.
[57 FR 10499, March 26, 1992]
Marijuana does not meet any of the elements for having a “currently accepted medical
use.”

47

 First, FDA broadly evaluated marijuana, and did not focus its evaluation on particular
strains of marijuana or components or derivatives of marijuana. Since different strains
may have different chemical constituents, marijuana, as identified in this petition, does
not have a known and reproducible chemistry, which would be needed to provide
standardized doses.
Second, there are not adequate safety studies on marijuana in the medical literature in
relation to a specific, recognized disorder. Third, there are no published adequate and
well controlled studies proving efficacy of marijuana. Fourth, there is no evidence that
qualified experts accept marijuana for use in treating a specific, recognized disorder.
Lastly, the scientific evidence regarding marijuana's chemistry in terms of a specific
Cannabis strain that could produce standardized and reproducible doses is not
currently available, so the scientific evidence on marijuana is not widely available.
Alternately, a Schedule II drug can be considered to have a “currently accepted
medical use with severe restrictions” (21 U.S.C. 812(b)(2)(B)). Yet as stated above,
the lack of accepted medical use for a specific, recognized disorder precludes the use
of marijuana even under conditions where its use is severely restricted.
In conclusion, to date, research on marijuana's medical use has not developed to the
point where marijuana is considered to have a “currently accepted medical use” or a
“currently accepted medical use with severe restrictions.”
3) There is a lack of accepted safety for use of marijuana under medical supervision:
There are currently no FDA-approved marijuana drug products. Marijuana does not
have a currently accepted medical use in treatment in the United States or a currently
accepted medical use with severe restrictions. Thus, FDA has not determined that
marijuana is safe for use under medical supervision.
In addition, FDA cannot conclude that marijuana has an acceptable level of safety
relative to its effectiveness in treating a specific, recognized disorder without evidence
that the substance is contamination free, and assurance of a consistent and predictable
dose. Investigations into the medical use of marijuana should include information and
data regarding the chemistry, manufacturing, and specifications of marijuana.
Additionally, a procedure for delivering a consistent dose of marijuana should also be
developed. Therefore, FDA concludes marijuana does not currently have an accepted
level of safety for use under medical supervision.

48

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The Medical Application of Marijuana: A Review of Published Clinical Studies
March 19, 2015
Prepared by:
U.S. Food and Drug Administration
Center for Drug Evaluation and Research (FDA/CDER)
Controlled Substance Staff (CSS)
Table of Contents
1. Introduction ................................................................................................................. 71
2. Methods ........................................................................................................................ 73
2.1 Define the Objective of the Review .................................................................................................... 73
2.2 Define “Marijuana” ............................................................................................................................. 73
2.3 Define “Adequate and Well-Controlled Clinical Studies” .................................................................. 74
2.4 Search Medical Literature Databases and Identify Relevant Studies .................................................. 74
2.5 Review and Analyze Qualifying Clinical Studies ............................................................................... 77

3. Results and Discussion ................................................................................................ 77
3.1 Neuropathic Pain ................................................................................................................................. 77
3.1.1 Neuropathic Pain Associated with HIV-Sensory Neuropathy ...................................................... 77
3.1.2 Central and Peripheral Neuropathic Pain ..................................................................................... 81
3.2 Appetite Stimulation in HIV ............................................................................................................... 85

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 3.3 Spasticity in Multiple Sclerosis ........................................................................................................... 88
3.4 Asthma ................................................................................................................................................ 89
3.5 Glaucoma ............................................................................................................................................ 91
3.6 Conclusions ......................................................................................................................................... 91
3.6.1 Conclusions for Chronic Neuropathic Pain .............................................................................. 91
3.6.2 Conclusions for Appetite Stimulation in HIV .......................................................................... 92
3.6.3 Conclusions for Spasticity in MS ............................................................................................. 92
3.6.4 Conclusions for Asthma ........................................................................................................... 92
3.6.5 Conclusions for Glaucoma ...................................................................................................... 93
3.7 Design Challenges for Future Studies ................................................................................................. 93
3.7.1 Sample Size .............................................................................................................................. 93
3.7.2 Marijuana Dose Standardization .............................................................................................. 94
3.7.3 Acute vs. Chronic Therapeutic Marijuana Use ......................................................................... 95
3.7.4 Smoking as a Route of Administration ..................................................................................... 96
3.7.5 Difficulty in Blinding of Drug Conditions ............................................................................... 96
3.7.6 Prior Marijuana Experience ...................................................................................................... 97
3.7.7 Inclusion and Exclusion Criteria .............................................................................................. 98
3.7.8 Number of Female Subjects ..................................................................................................... 98

Appendix (Tables) ......................................................................................................... 103
List of Figure
Figure 1: Identification of Studies from PubMed Search ........................................... 76
List of Tables
Table 1: Randomized, controlled, double-blind trials examining smoked marijuana in
treatment of neuropathic pain ......................................................................................... 103
Table 2: Randomized, controlled, double-blind trials examining smoked marijuana in
treatment of appetite stimulation in HIV/AIDS .............................................................. 108
Table 3: Randomized, controlled, double-blind trails examining smoked marijuana in
treatment of spasticity in Multiple Sclerosis ................................................................... 111
Table 4: Randomized, controlled, double-blind trails examining smoked marijuana in
treatment of intraocular pressure in Glaucoma ............................................................... 112
Table 5: Randomized, controlled, double-blind trails examining smoked marijuana in
treatment of asthma ......................................................................................................... 114
Executive Summary
Marijuana is a Schedule I substance under the Controlled Substances Act (CSA).
Schedule I indicates a high potential for abuse, no currently accepted medical use
in the United States, and a lack of accepted safety for use under medical
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 supervision. To date, marijuana has not been subject to an approved new drug
application (NDA) that demonstrates its safety and efficacy for a specific
indication under the Food Drug and Cosmetic Act (FDCA).
Nevertheless, as of October 2014, twenty-three states and the District of
Columbia have passed state-level medical marijuana laws that allow for marijuana
use within that state; similar bills are pending in other states.
The present review was undertaken by the Food and Drug Administration (FDA)
to analyze the clinical studies published in the medical literature investigating the
use of marijuana in any therapeutic areas. First, we discuss the context for this
scientific review. Next, we describe the methods used in this review to identify
adequate and well-controlled studies evaluating the safety and efficacy of
marijuana for particular therapeutic uses.
The FDA conducted a systematic search for published studies in the medical
literature that meet the described criteria for study design and outcome measures
prior to February 2013. While not part of our systematic review, we have
continued to routinely follow the literature beyond that date for subsequent
studies. Studies were considered to be relevant to this review if the investigators
administered marijuana to patients with a diagnosed medical condition in a wellcontrolled, double-blind, placebo-controlled clinical trial. Of the eleven studies
that met the criteria for review, five different therapeutic areas were investigated:
 Five studies examined chronic neuropathic pain
 Two studies examined appetite stimulation in human immunodeficiency
virus (HIV) patients
 Two studies examined glaucoma
 One study examined spasticity and pain in multiple sclerosis (MS)
 One study examined asthma.
For each of these eleven clinical studies, information is provided regarding the
subjects studied, the drug conditions tested (including dose and method of
administration), other drugs used by subjects during the study, the physiological
and subjective measures collected, the outcome of these measures comparing
treatment with marijuana to placebo, and the reported and observed adverse
events. The conclusions drawn by the investigators are then described, along with
potential limitations of these conclusions based on the study design. A brief
summary of each study’s findings and limitations is provided at the end of the
section.
The eleven clinical studies that met the criteria and were evaluated in this review showed
positive signals that marijuana may produce a desirable therapeutic outcome, under the
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 specific experimental conditions tested. Notably, it is beyond the scope of this review to
determine whether these data demonstrate that marijuana has a currently accepted
medical use in the United States. However, this review concludes that these eleven
clinical studies serve as proof-of-concept studies, based on the limitations of their study
designs, as described in the study summaries. Proof-of-concept studies provide
preliminary evidence on a proposed hypothesis regarding a drug’s effect. For drugs
under development, the effect often relates to a short-term clinical outcome being
investigated. Proof-of-concept studies serve as the link between preclinical studies and
dose ranging clinical studies. Therefore, proof-of-concept studies are not sufficient to
demonstrate efficacy of a drug because they provide only preliminary information about
the effects of a drug. However, the studies reviewed produced positive results,
suggesting marijuana should be further evaluated as an adjunct treatment for neuropathic
pain, appetite stimulation in HIV patients, and spasticity in MS patients.
The main limitations identified in the eleven studies testing the medical applications of
marijuana are listed below:
 The small numbers of subjects enrolled in the studies, which limits the statistical
analyses of safety and efficacy.
 The evaluation of marijuana only after acute administration in the studies, which
limits the ability to determine efficacy following chronic administration.
 The administration of marijuana typically through smoking, which exposes ill
patients to combusted material and introduces problems with determining the
doses delivered.
 The potential for subjects to identify whether they received marijuana or placebo,
which breaks the blind of the studies.
 The small number of cannabinoid naïve subjects, which limits the ability to
determine safety and tolerability in these subjects.
 The low number of female subjects, which makes it difficult to generalize the
study findings to subjects of both genders.
Thus, this review discusses the following methodological changes that may be
made in order to resolve these limitations and improve the design of future studies
which examine the safety and efficacy of marijuana for specific therapeutic
indications:
 Determine the appropriate number of subjects studied based on
recommendations in various FDA Guidances for Industry regarding the
conduct of clinical trials for specific medical indications.

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  Administer consistent and reproducible doses of marijuana based on
recommendations in the FDA Guidance for Industry: Botanical Drug
Products (2004)27.
 Evaluate the effects of marijuana under therapeutic conditions following
both acute and chronic administration.
 Consider alternatives to smoked marijuana (e.g., vaporization).
 Address and improve whenever possible the difficulty in blinding of
marijuana and placebo treatments in clinical studies.
 Evaluate the effect of prior experience with marijuana with regard to the
safety and tolerability of marijuana.
 Strive for gender balance in the subjects used in studies.
In conclusion, the eleven clinical studies conducted to date do not meet the
criteria required by the FDA to determine if marijuana is safe and effective in
specific therapeutic areas. However, the studies can serve as proof-of-concept
studies and support further research into the use of marijuana in these therapeutic
indications. Additionally, the clinical outcome data and adverse event profiles
reported in these published studies can beneficially inform how future research in
this area is conducted. Finally, application of the recommendations listed above
by investigators when designing future studies could greatly improve the available
clinical data that can be used to determine if marijuana has validated and reliable
medical applications.

27

This Guidance is available on the internet at http://www.fda.gov/Drugs/default.htm under Guidance
(Drugs).

70

 1. Introduction
In response to citizen petitions submitted to the Drug Enforcement Administration
(DEA) requesting DEA to reschedule marijuana, the DEA Administrator
requested that the U.S. Department of Health and Human Services (HHS) provide
a scientific and medical evaluation of the available information and a scheduling
recommendation for marijuana, in accordance with 21 U.S.C. 811(b). The
Secretary of HHS is required to consider in a scientific and medical evaluation
eight factors determinative of control under the Controlled Substance Act (CSA).
Administrative responsibilities for evaluating a substance for control under the
CSA are performed by the Food and Drug Administration (FDA), with the
concurrence of the National Institute on Drug Abuse (NIDA). Part of this
evaluation includes an assessment of whether marijuana has a currently accepted
medical use in the United States. This assessment necessitated a review of the
available data from published clinical studies to determine whether there is
adequate scientific evidence of marijuana’s effectiveness.
Under Section 202 of the CSA, marijuana is currently controlled as a Schedule I
substance (21 U.S.C § 812). Schedule I includes those substances that have a
high potential for abuse, have no currently accepted medical use in treatment in
the United States, and lack accepted safety for use under medical supervision (21
U.S.C. § 812(b)(1)(A)-(C)).
A drug product which has been approved by FDA for marketing in the United
States is considered to have a “currently accepted medical use.” Marijuana is not
an FDA-approved drug product, as a New Drug Application (NDA) or Biologics
License application (BLA) for marijuana has not been approved by FDA.
However, FDA approval of an NDA is not the only means through which a drug
can have a currently accepted medical use in the United States.
In general, a drug may have a “currently accepted medical use” in the United States if the
drug meets a five-part test. Established case law (Alliance for Cannabis Therapeutics v.
DEA, 15 F.3d 1131, 1135 (D.C. Cir. 1994)) upheld the Administrator of DEA’s
application of the five-part test to determine whether a drug has a “currently accepted
medical use.” The following describes the five elements that characterize “currently
accepted medical use” for a drug28:
i.

the drug's chemistry must be known and reproducible
“The substance’s chemistry must be scientifically established
to permit it to be reproduced into dosages which can be
standardized. The listing of the substance in a current edition of
one of the official compendia, as defined by section 201(j) of

28

57 FR 10499, 10504-06 (March 26, 1992).

71

 the Food, Drug and Cosmetic Act, 21 U.S.C. 321(j), is
sufficient to meet this requirement.”
ii. there must be adequate safety studies
“There must be adequate pharmacological and toxicological
studies, done by all methods reasonably applicable, on the
basis of which it could fairly and responsibly be concluded, by
experts qualified by scientific training and experience to
evaluate the safety and effectiveness of drugs, that the
substance is safe for treating a specific, recognized disorder.”
iii. there must be adequate and well-controlled studies proving efficacy
“There must be adequate, well-controlled, well-designed, wellconducted, and well-documented studies, including clinical
investigations, by experts qualified by scientific training and
experience to evaluate the safety and effectiveness of drugs, on
the basis of which it could be fairly and responsibly concluded
by such experts that the substance will have the intended effect
in treating a specific, recognized disorder.”
iv. the drug must be accepted by qualified experts
“The drug has a New Drug Application (NDA) approved by
the Food and Drug Administration, pursuant to the Food, Drug
and Cosmetic Act, 21 U.S.C. 355. Or, a consensus of the
national community of experts, qualified by scientific training
and experience to evaluate the safety and effectiveness of
drugs, accepts the safety and effectiveness of the substance for
use in treating a specific, recognized disorder. A material
conflict of opinion among experts precludes a finding of
consensus.” and
v. the scientific evidence must be widely available.
“In the absence of NDA approval, information concerning the
chemistry, pharmacology, toxicology, and effectiveness of the
substance must be reported, published, or otherwise widely
available, in sufficient detail to permit experts, qualified by
scientific training and experience to evaluate the safety and
effectiveness of drugs, to fairly and responsibly conclude the
substance is safe and effective for use in treating a specific,
recognized disorder.”

72

 One way to pass the five-part test for having “currently accepted medical use” is
through submission of an NDA or BLA which is approved by FDA. However,
FDA approval of an NDA or BLA is not required for a drug to pass the five-part
test.
This review focuses on FDA’s analysis of one element of the five-part test for
determining whether a drug has “currently accepted medical use”. Specifically,
the present review assesses the 3rd criterion that addresses whether marijuana has
“adequate and well-controlled studies proving efficacy”. Thus, this review
evaluates published clinical studies that have been conducted using marijuana in
subjects who have a variety of medical conditions by assessing the adequacy of
the summarized study designs and the study data. The methodology for selecting
the studies that were evaluated is delineated below.
FDA’s evaluation and conclusions regarding the remaining four criteria for
whether marijuana has a “currently accepted medical use,” as well as the eight
factors pertaining to the scheduling of marijuana, are outside the scope of this
review. A detailed discussion of these factors is contained in FDA’s scientific
and medical evaluation of marijuana.
2. Methods
The methods for selecting the studies to include in this review involved the
following steps, which are described in detail in the subsections below:
1. Define the objective of the review.
2. Define “marijuana” in order to facilitate the medical literature search for
studies that administered the substance,
3. Define “adequate and well-controlled studies” in order to facilitate the
search for relevant data and literature,
4. Search medical literature databases and identify relevant adequate and
well-controlled studies, and
5. Review and analyze the adequate and well-controlled clinical studies to
determine if they demonstrate efficacy of marijuana for any therapeutic
indication.
2.1 Define the Objective of the Review
The objective of this review is to assess the study designs and resulting data from
clinical studies published in the medical literature that were conducted with
marijuana (as defined below) as a treatment for any therapeutic indication, in
order to determine if they meet the criteria of “adequate and well-controlled
studies proving efficacy”.
2.2 Define “Marijuana”

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 In this review, the term “marijuana” refers to the flowering tops or leaves of the
Cannabis plant. There were no restrictions on the route of administration used for
marijuana in the studies.
Studies which administered individual cannabinoids (whether experimental
substances or marketed drug products) or marijuana extracts were excluded from
this review. Additionally, studies of administered neutral plant material or
placebo marijuana (marijuana with all cannabinoids extracted) that had
subsequently been supplemented by the addition of specific amounts of THC or
other cannabinoids were also excluded (Chang et al., 1979).
2.3 Define “Adequate and Well-Controlled Clinical Studies”
The criteria for an “adequate and well-controlled study” for purposes of
determining the safety and efficacy of a human drug is defined under the Code of
Federal Regulations (CFR) in 21 CFR 314.126. The elements of an adequate and
well-controlled study as described in 21 CFR 314.126 can be summarized as
follows:
1.
2.
3.
4.
5.
6.
7.
8.

The main objective must be to assess a therapeutically relevant outcome.
The study must be placebo-controlled.
The subjects must qualify as having the medical condition being studied.
The study design permits a valid comparison with an appropriate control
condition.
The assignment of subjects to treatment and control groups must be
randomized.
There is minimization of bias through the use of a double-blind study
design.
The study report contains a full protocol and primary data.
Analysis of the study data is appropriately conducted.

As noted above, the current review examines only those data available in the
public domain and thus relies on clinical studies published in the medical
literature. Published studies by their nature are summaries that do not include the
level of detail required by studies submitted to FDA in an NDA.
While the majority of the elements defining an adequate and well-controlled study
can be satisfied through a published paper (elements #1-6), there are two elements
that cannot be met by a study published in the medical literature: element #7
(availability of a study report with full protocol and primary data) and element #8
(a determination of whether the data analysis was appropriate). Thus, for
purposes of this review, only elements #1-6 will be used to qualify a study as
being adequate and well-controlled.
2.4 Search Medical Literature Databases and Identify Relevant Studies
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 We identified randomized, double-blind, placebo-controlled clinical studies
conducted with marijuana to assess marijuana’s efficacy in any therapeutic
indication. Two primary medical literature databases were searched for all studies
posted to the databases prior to February 201329:
 PubMed: PubMed is a database of published medical and scientific studies
that is maintained by the U.S. National Library of Medicine (NLM) at
NIH as a part of the Entrez system of information retrieval. PubMed
comprises more than 24 million citations for biomedical literature from
MEDLINE, life science journals, and online books
(http://www.ncbi.nlm.nih.gov/pubmed).
 ClinicalTrials.gov: ClinicalTrials.gov is a database of publicly and
privately supported clinical studies that is maintained by the NLM.
Information about the clinical studies is provided by the Sponsor or
Principal Investigator of the study. Information about the studies is
submitted to the website (“registered”) when the studies begin, and is
updated throughout the study. In some cases, results of the study or
resulting publication citations are submitted to the website after the study
ends (https://clinicaltrials.gov/ct2/about-site/background).
ClinicalTrials.gov was searched for all studies administering marijuana. The
results of this search were used to confirm that no completed studies with
published data were missed in the literature search. During the literature search,
references found in relevant studies and systematic reviews were evaluated for
additional relevant citations. All languages were included in the search. The
PubMed search yielded a total of 566 abstracts30. Of these abstracts, a full-text
review was conducted with 85 papers to assess eligibility. From this evaluation,
only eleven of 85 studies met the 6 CFR elements for inclusion as adequate and
well-controlled studies.
Figure 1 (below) provides an overview of the process used to identify studies
from the PubMed search. The eleven studies reviewed were published between
1974 and 2013. Ten of these studies were conducted in the United States and one
study was conducted in Canada. These eleven studies examined the effects of
smoked and vaporized marijuana for the indications of chronic neuropathic pain,
spasticity related to multiple sclerosis (MS), appetite stimulation in patients with
human immunodeficiency virus (HIV), glaucoma, and asthma. All included
studies used adult patients as subjects. All studies conducted in the United States
were conducted under an IND as Phase 2 investigations.
29

While not a systematic review, we have followed the recent published literature on marijuana use for
possible therapeutic purposes and, as of January 2015, we found only one new study that would meet our
criteria (Naftali et al., 2013). This study examined the effects of smoked marijuana on Crohn’s disease.
30
The following search strategy was used, “(cannabis OR marijuana) AND (therapeutic use OR therapy)
AND (RCT OR randomized controlled trial OR "systematic review" OR clinical trial OR clinical trials)
NOT ("marijuana abuse"[Mesh] OR addictive behavior OR substance related disorders)”.

75

 Figure 1: Identification of Studies from PubMed Search
566 Abstracts identified in PubMed search
481 Excluded because either clearly
a
b
irrelevant , excluded article type , or not
c
RCT

85 Full-text articles assessed for eligibility
76 Excluded
d
63 Administered individual cannabinoids or
marijuana plant derived products
9
27 Administered delta -THC
20 Administered marijuana plant extracts
4 Administered Cannabidiol
4 Administered hemp seed oil
e
1 Administered Rimonabant
6 Were mechanistic studies
7 Had a primary focus on safety

f

9 Articles from the PubMed search meet inclusion criteria
a

Articles were deemed irrelevant if they examined safety or adverse event related outcomes,
b
including psychoactive effects or other adverse events. Excluded article types included
c
comments, reviews, meta-analyses, and news articles. Randomized Controlled Trials.
d
e
Cannabinoids administered included synthetic cannabinoids. Rimonabant is a cannabinoid
f
receptor antagonist. An additional 2 studies meeting the inclusion criteria were found through
the reference search.

Two qualifying studies, which assessed marijuana for glaucoma, were previously
reviewed in the 1999 Institute of Medicine (IOM) report entitled “Marijuana and
Medicine: Assessing the Science Base”31. We did our own analysis of these two
studies and concurred with the conclusions in the IOM report. Thus, a detailed
discussion of the two glaucoma studies is not included in the present review. The
present review only discusses 9 of the identified 11 studies. For a summary of the
study design for all eleven qualifying studies, see Tables 1-5 (located in the
Appendix).

31

In January 1997, the White House Office of National Drug Control Policy (ONDCP) requested that the
IOM conduct a review of the scientific evidence to assess the potential health benefits and risks of
marijuana and its constituent cannabinoids. Information for this study was gathered through scientific
workshops, site visits to cannabis buyers’ clubs and HIV/Acquired Immunodeficiency Syndrome (AIDS)
clinics, analysis of the relevant scientific literature, and extensive consultation with biomedical and social
scientists. The report was finalized and published in 1999.

76

 Based on the selection criteria for relevant studies described in Section 2.3
(Define Adequate and Well-Controlled Clinical Studies), a number of clinical
studies that investigated marijuana, as defined in this review, were excluded from
this review. Studies that examined the effects of marijuana in healthy subjects
were excluded because they did not test a patient population with a medical
condition (Flom et al., 1975; Foltin et al., 1986; Foltin et al., 1988; Hill et al.,
1974; Milstein et al., 1974; Milstein et al., 1975; Soderpalm et al., 2001; Wallace
et al., 2007; Greenwald and Stitzer, 2000). A 1975 study by Tashkin et al. was
excluded because it had a single-blind, rather than double-blind, study design.
Two other studies were excluded because the primary outcome measure assessed
safety rather than a therapeutic outcome (Greenberg et al., 1994; Abrams et al.,
2003).
2.5 Review and Analyze Qualifying Clinical Studies
Qualified clinical studies that evaluated marijuana for therapeutic purposes were
examined in terms of adequacy of study design including method of drug
administration, study size, and subject inclusion and exclusion criteria.
Additionally, the measures and methods of analysis used in the studies to assess
the treatment effect were examined.
3. Results and Discussion
The eleven qualifying studies in this review assessed a variety of therapeutic
indications. In order to better facilitate analysis and discussion of the studies, the
following sections group the studies by therapeutic area. Within each section,
each individual study is summarized in terms of its design, outcome data and
important limitations. This information is also provided in the Appendix in
tabular form for each study.
3.1 Neuropathic Pain
Five randomized, double-blind, placebo-controlled Phase 2 clinical studies have
been conducted to examine the effects of inhaled marijuana smoke on
neuropathic pain associated with HIV-sensory neuropathy (Abrams et al., 2007;
Ellis et al., 2009) and chronic neuropathic pain from multiple causes (Wilsey et
al., 2008; Ware et al., 2010; Wilsey et al., 2013). Table 1 of the Appendix
summarizes these studies.
3.1.1 Neuropathic Pain Associated with HIV-Sensory Neuropathy
Two studies examined the effect of marijuana to reduce the pain induced by HIVsensory neuropathy.
Abrams et al. (2007) conducted the first study entitled, “Cannabis in painful
HIV-associated sensory neuropathy: a randomized placebo-controlled trial”. The
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 subjects were 50 adult patients with uncontrolled HIV-associated sensory
neuropathy, who had at least 6 experiences with smoking marijuana. The subjects
were split into two parallel groups of 25 subjects each. More than 68% of
subjects were current marijuana users, but all individuals were required to
discontinue using marijuana prior to the study. Most subjects were taking
medication for pain during the study, with the most common medications being
opioids and gabapentin. Upon entry into the study, subjects had an average daily
pain score of at least 30 on a 0-100 visual analog scale (VAS).
Subjects were randomized to receive either smoked marijuana (3.56% THC32) or
smoked placebo cigarettes three times per day for 5 days, using a standardized
cued smoking procedure: (1) 5 second inhale, (2) 10 second holding smoke in the
lungs, (3) 40 second exhale and breathing normally between puffs. The authors
did not specify how many puffs the subjects smoked at each smoking session, but
they stated that one cigarette was smoked per smoking session.
Primary outcome measures included daily VAS ratings of chronic pain and the
percentage of subjects who reported a result of more than 30% reduction in pain
intensity. The ability of smoked marijuana to induce acute analgesia was assessed
using both thermal heat model and capsaicin sensitization model, while antihyperalgesia was assessed with brush and von Frey hair stimuli. The immediate
analgesic effects of smoked marijuana was assessed using a 0-100 point VAS at
40-minute intervals three times before and three times after the first and last
smoking sessions, which was done to correspond to the time of peak plasma
cannabinoid levels. Notably, not all subjects completed the induced pain portion
of the study (n = 11 in marijuana group, 9 in placebo group) because of their
inability to tolerate the stimuli. Throughout the study, subjects also completed the
Profile of Mood States (POMS) questionnaire, as well as subjective VAS
measures of anxiety, sedation, disorientation, paranoia, confusion, dizziness, and
nausea.
As a result, the median daily pain was reduced 34% by smoked marijuana
compared to 17% by placebo (p = 0.03). Fifty-two percent of subjects who
smoked marijuana reported a >30% reduction in pain compared to 24% in the
placebo group (p = 0.04). Although marijuana reduced experimentally-induced
hyperalgesia (p ≤ 0.05) during the first smoking sessions, marijuana did not alter
responses to acutely painful stimuli.
There were no serious AEs and no episodes of hypertension, hypotension, or
tachycardia requiring medical intervention. No subjects withdrew from the study
for drug related reasons. Subjects in the marijuana group reported higher ratings
on the subjective measures of anxiety, sedation, disorientation, confusion, and
32

The drug dose is reported as percentage of THC present in the marijuana rather than milligrams of THC
present in each cigarette because of the difficulty in determining the amount of THC delivered by
inhalation (see discussion in the section entitled “3.7.2 Marijuana Dose Standardization”).

78

 dizziness compared to the placebo group. There was one case of severe dizziness
in a marijuana-treated subject. By the end of the study, subjects treated with
marijuana and placebo reported a reduction in total mood disturbance as measured
by POMS.
The authors conclude that smoked marijuana effectively reduced chronic
neuropathic pain from HIV-associated sensory neuropathy with tolerable side
effects. However, limitations of this study include: maintenance of subjects on
other analgesic medication while being tested with marijuana and a lack of
information about the number of puffs during each inhalation of smoke. These
limitations make it difficult to conclude that marijuana has analgesic properties on
its own and that the actual AEs experienced during the study in response to
marijuana are tolerable. However, the study produced positive results suggesting
that marijuana should be studied further as an adjunct treatment for uncontrolled
HIV-associated sensory neuropathy.
Ellis et al. (2009) conducted a more recent study entitled “Smoked medicinal
cannabis for neuropathic pain in HIV: a randomized, crossover clinical trial”. The
subjects were 28 HIV-positive adult male patients with intractable neuropathic
pain that was refractory to the effects of at least two drugs taken for analgesic
purposes. Upon entry into the study, subjects had a mean score of > 5 on the Pain
Intensity subscale of the Descriptor Differential Scale (DDS). Subjects were
allowed to continue taking their current routine of pain medications, which
included opioids, non-narcotic analgesics, antidepressants, and anticonvulsants.
Previous experience with marijuana was not required for participation in the
study, but 27 of 28 subjects (96%) reported previous experience with marijuana.
However, of these 27 experienced subjects, 63% (n = 18) reported no marijuana
use within the past year.
The study procedures compared the effects of the target dose of marijuana and
placebo during two treatment periods lasting 5 days, with 2 weeks washout
periods. The marijuana strengths available were 1%, 2%, 4%, 6%, or 8% THC
concentration by weight. Subjects smoked marijuana or placebo cigarettes four
times per day, approximately 90-120 minutes apart, using a standardized cued
smoking procedure: (1) 5 second smoke inhalation, (2) 10 second hold of smoke
in lungs, (3) 40 second exhale and normal breathing between puffs. The
investigators did not provide a description of the number of puffs taken at any
smoking session. All subjects practiced the smoking procedures using placebo
marijuana prior to test sessions.
On the first day of each test period, dose titration occurred throughout the four
smoking sessions scheduled for that day, with a starting strength of 4% THC
concentration. Subjects were allowed to titrate to a personalized “target dose”,
which was defined as the dose that provided the best pain relief without
intolerable adverse effects. This dose titration was accomplished by allowing
subjects to either increase the dose incrementally (to 6% or 8% THC) to improve
79

 analgesia, or to decrease the dose incrementally (to 1% or 2% THC) if AEs were
intolerable. For the next 4 days of each test period, the subjects smoked their
target dose during each of the four daily smoking sessions. To maintain the blind,
placebo marijuana was represented as containing 1%-8% THC, even though it did
not contain any cannabinoids.
The primary outcome measure was the change in pain magnitude on the DDS at
the end of each test period compared to baseline, with a clinically significant level
of analgesia considered to be a reduction in pain of at least 30%. Additional
measures included the POMS, the Sickness Impact Profile (SIP), the Brief
Symptom Inventory (BSI) and the UKU Side Effect Rating Scale and a subjective
highness/sedation VAS.
During the marijuana treatment week, 19 subjects titrated to the 2%-4% THC
dose while the 6%-8% dose was preferred by 8 subjects and 1 subject chose the
1% dose. In contrast, during the placebo treatment week, all 28 subjects titrated
to the highest possible dose of “8% THC” that contained no actual cannabinoids,
suggesting that placebo treatment provided little analgesic relief.
The degree of pain reduction was significantly greater after administration of
marijuana compared to placebo (median change of 3.3 points on DDS, p=0.016).
The median change from baseline in VAS pain scores was −17 for marijuana
treatment compared to −4 for placebo treatment (p<0.001). A larger proportion of
subjects who were treated with marijuana (0.46) reported a >30% reduction in
pain, compared to placebo (0.18). Additionally, the authors report improvements
in total mood disturbance, physical disability, and quality of life as measured on
POMS, SIP, and BSI scales after both placebo and marijuana treatment (data not
provided in paper).
In terms of safety, there were no alterations in HIV disease parameters in response
to marijuana or placebo. The authors report that marijuana led to a greater degree
of UKU responses as well as AEs such as difficulty in concentration, fatigue,
sleepiness or sedation, increased duration of sleep, reduced salivation and thirst
compared to placebo (data not provided in paper). Two subjects withdrew from
the study because of marijuana-related AEs: one subject developed an intractable
smoking-related cough during marijuana administration and the sole marijuananaïve subject in the study experienced an incident of acute cannabis-induced
psychosis33.
The authors conclude that smoked marijuana effectively reduced chronic
neuropathic pain from HIV-associated sensory neuropathy. The limitations of
33

At the time of the study, the following criteria from the Diagnostic and Statistical Manual of Mental
Disorders (DSM-IV-TR, 2000) were used to diagnose substance-induced psychotic disorders: Prominent
hallucinations or delusions; Hallucinations and/or delusions that develop during, or within one month of,
intoxication or withdrawal; The disturbance is not better accounted for by a psychotic disorder that is not
substance induced. The disturbance does not occur exclusively during the course of a delirium.

80

 this study include: a lack of information about the number of puffs during each
inhalation of smoke; a lack of information about the specific timing of the
subjective assessments and collection of AEs relative to initiation of the smoking
sessions; and the inclusion of only one marijuana-naïve subject. These limitations
make it difficult to conclude that the actual AEs experienced during the study in
response to marijuana are tolerable. It is especially concerning that the only
marijuana-naïve subject left the study because of serious psychiatric responses to
marijuana exposure at analgesic doses. However, the study produced positive
results suggesting that marijuana should be studied further as an adjunct treatment
for uncontrolled HIV-associated sensory neuropathy.
3.1.2 Central and Peripheral Neuropathic Pain
Three studies examined the effect of marijuana on chronic neuropathic pain.
Wilsey et al. (2008) examined chronic neuropathic pain from multiple causes in
the study entitled, “A Randomized, Placebo-Controlled, Crossover Trial of
Cannabis Cigarettes in Neuropathic Pain”. The subjects were 32 patients with a
variety of neuropathic pain conditions, including 22 with complex regional pain
syndrome, 6 with spinal cord injury, 4 with multiple sclerosis, 3 with diabetic
neuropathy, 2 with ilioinguinal neuralgia, and 1with lumbosacral plexopathy. All
subjects reported a pain intensity of at least 30 on a 0-100 VAS and were allowed
to continue taking their regular medications during the study period, which
included opioids, antidepressants, anticonvulsants, and NSAIDs. All subjects
were required to have experience with marijuana but could not use any
cannabinoids for 30 days before study sessions.
The study consisted of three test sessions with an interval of 3-21 days between
sessions. Treatment conditions were high-strength marijuana (7% delta-9-THC),
low-strength marijuana (3.5% delta-9-THC), and placebo cigarettes, administered
through a standardized cued-puff procedure: (1) “light the cigarette” (30 seconds),
(2) “get ready” (5 seconds), (3) “inhale” (5 seconds), (4) “hold smoke in lungs”
(10 seconds), (5) “exhale,” and (6) wait before repeating the puff cycle (40
seconds). Participants took 2 puffs after baseline measurements, 3 puffs an hour
later, and 4 puffs an hour after that, for a cumulative dose of 9 puffs per test
session.
Hourly assessment periods were scheduled before and after each set of puffs and
for 2 additional hours during the recovery period. Plasma cannabinoids were
measured at baseline, 5 minutes after the first puff and again at 3 hours after the
last puff cycle.
The primary outcome measure was spontaneous pain relief, as measured by a 0100 point VAS for current pain. Pain unpleasantness was measured on a 0-100
point VAS, and degree of pain relief was measured on a 7-point Patient Global
Impression of Change (PGIC) scale. Secondary measures included the
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 Neuropathic Pain Scale (NPS), a 0-100 point VAS for allodynia, and changes in
thermal pain threshold. Subjective measures were also evaluated with unipolar 0100 point VAS for any drug effect, good drug effect, bad drug effect, high, drunk,
impaired, stoned, like the drug effect, sedated, confused, nauseated, desire more
of the drug, anxious, down, hungry, and bipolar 0-100 point VAS for sad/happy,
anxious/relaxed, jittery/calm, bad/good, paranoid/self-assured, fearful/unafraid.
Neurocognitive assessments measured attention and concentration, learning and
memory, and fine motor speed.
Marijuana produced a reduction in pain compared to placebo, as measured by the
pain VAS, the PGIC and on pain descriptors in the NPS, including sharp (P <
.001), burning (P < .001), aching (P < .001), sensitive (P = .03), superficial (P <
.01) and deep pain (P < .001). Notably, there were no additional benefits from the
7% THC strength of marijuana compared to the 3.5% THC strength, seemingly
because of cumulative drug effects over time. There were no changes in allodynia
or thermal pain responsivity following administration of either dose of marijuana.
Marijuana at both strengths produced increases on measures of any drug effect,
good drug effect, high, stoned, impairment, sedation, confusion, and hunger. The
7% THC marijuana increased anxiety scores and bad drug effect (later in session)
compared to placebo. Neither strength of marijuana affected the measures of
mood. On neurocognitive measures, both the 3.5% THC and 7% THC marijuana
produced impairment in learning and memory, while only the 7% THC marijuana
impaired attention and psychomotor speed, compared to placebo. There were no
adverse cardiovascular side effects and no subjects dropped out because of an
adverse event related to marijuana.
The authors conclude that marijuana may be effective at ameliorating neuropathic
pain at doses that induce mild cognitive effects, but that smoking is not an
optimum route of administration. The limitations of this study include: inclusion
of subjects with many forms of neuropathic pain and maintenance of subjects on
other analgesic medication while being tested with marijuana. These limitations
make it difficult to conclude that marijuana has analgesic properties on its own
and that the actual AEs experienced during the study in response to marijuana are
tolerable. The authors compared pain score results by the type of pain condition,
with no significant differences found; however, the sample size of this study was
small thus a type II error may have been present. Thus, it is difficult to determine
if any particular subset of neuropathic pain conditions would benefit specifically
from marijuana administration. However, the study produced positive results
suggesting that marijuana should be studied further as an adjunct treatment for
uncontrolled neuropathic pain.
The second study, conducted by Ware et al. (2010) in Canada is entitled,
“Smoked cannabis for chronic neuropathic pain: a randomized controlled trial”.
The subjects were 21 adult patients with neuropathic pain caused by trauma or
surgery compounded with allodynia or hyperalgesia, and a pain intensity score
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 greater than 4 on a 10 point VAS. All subjects maintained their current analgesic
medication and they were allowed to use acetaminophen for breakthrough pain.
Eighteen subjects had previous experience with marijuana but none of them had
used marijuana within a year before the study.
The study design used a four-period crossover design, testing marijuana (2.5%,
6.0% and 9.4% THC) and placebo marijuana. The 2.5% and 6.0% doses of
marijuana were included to increase successful blinding. Each period was 14
days in duration, beginning with 5 days on the study drug followed by a 9-day
washout period. Doses were delivered as 25 mg of marijuana that was smoked in
a single inhalation using a titanium pipe. The first dose of each period was selfadministered using a standardized puff procedure: (1) inhale for 5 seconds, (2)
hold the smoke in their lungs for 10 seconds, and (3) exhale. Subsequent doses
were self-administered in the same manner for a total of three times daily at home
on an outpatient basis for the first five days of each period.
The primary measure was an 11-point pain intensity scale, averaged over the 5
day treatment period, which was administered once daily for present, worst, least
and average pain intensity during the previous 24 hours. Secondary measures
included an acute pain 0-100 point VAS, pain quality assessed with the McGill
Pain Questionnaire, sleep assessed with the Leeds Sleep Evaluation
Questionnaire, mood assessed with the POMS, quality of life assessed using the
EQ-5D health outcome instrument. Subjective measures included 0-100 point
VAS scales for high, relaxed, stressed and happy.
Over the first three hours after smoking marijuana, ratings of pain, high,
relaxation, stress, happiness and heart rate were recorded. During the five days of
each study period, participants were contacted daily to administer questionnaires
on pain intensity, sleep, medication and AEs. Subjects returned on the fifth day to
complete questionnaires on pain quality, mood, quality of life and assessments of
potency. At the end of the study, participants completed final adverse event
reports and potency assessments.
The average daily pain intensity was significantly lower on 9.4% THC marijuana
(5.4) than on placebo marijuana (6.1) (p = 0.023). The 9.4% THC strength also
produced more drowsiness, better sleep, with less anxiety and depression,
compared to placebo (all p < 0.05). However, there were no significant
differences on POMS scores or on VAS scores for high, happy, relaxed or
stressed between THC doses.
The most frequent drug-related adverse events reported in the group receiving
9.4% THC marijuana were headache, dry eyes, burning sensation, dizziness,
numbness and cough. Reports of high and euphoria occurred on only three
occasions, once in each dose of THC. There were no significant changes in vital
signs, heart-rate variability, or renal function. One subject withdrew from the
study due to increased pain during administration of 6% THC marijuana.
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 The authors conclude that smoked marijuana reduces neuropathic pain, improves
mood and aids in sleep, but that smoking marijuana is not a preferable route of
administration. The limitations of this study include: the lack of information on
timing of assessments during the outpatient portion of the study and maintenance
of subjects on other analgesic medication while being tested with marijuana.
These limitations make it difficult to conclude that marijuana has analgesic
properties on its own and that the actual AEs experienced during the study in
response to marijuana are tolerable. However, the study produced positive results
suggesting that marijuana should be studied further as an adjunct treatment for
uncontrolled neuropathic pain.
Wilsey et al. (2013) conducted the most recent study entitled, “Low-Dose
Vaporized Cannabis Significantly Improves Neuropathic Pain”. This study is the
only one in this review that utilized vaporization as a method of marijuana
administration. The subjects were 36 patients with a neuropathic pain disorder
(CRPS, thalamic pain, spinal cord injury, peripheral neuropathy, radiculopathy, or
nerve injury) who were maintained on their current medications (opioids,
anticonvulsants, antidepressants, and NSAIDs). Although subjects were required
to have a history of marijuana use, they refrained from use of cannabinoids for 30
days before study sessions.
Subjects participated in three sessions in which they received 1.29% or 3.53%
THC marijuana or placebo marijuana. The marijuana was vaporized using the
Volcano vaporizer and a standardized cued-puff procedure: (1) “hold the
vaporizer bag with one hand and put the vaporizer mouthpiece in their mouth” (30
seconds), (2) “get ready” (5 seconds), (3) “inhale” (5 seconds), (4) “hold vapor in
lungs” (10 seconds), (5) “exhale and wait” before repeating puff cycle (40
seconds). Subjects inhaled 4 puffs at 60 minutes. At 180 minutes, the vaporizer
was refilled with marijuana vapor and subjects were allowed to inhale 4 to 8 puffs
using the cued procedure. Thus, cumulative dosing allowed for a range of 8 to12
puffs in total for each session, depending on the subjects desired response and
tolerance. The washout time between each session ranged from 3-14 days.
The primary outcome variable was spontaneous pain relief, as assessed using a 0100 point VAS for current pain. Secondary measures included the Patient Global
Impression of Change (PGIC), the Neuropathic Pain Scale (NPS), a 0-100 point
VAS for allodynia. Acute pain threshold was measured with a thermal pain
model. Subjective measures included 0-100 point unipolar VAS for any drug
effect, good drug effect, bad drug effect, high, drunk, impaired, stoned, drug
liking, sedated, confused, nauseated, desire more drug, anxious, down and
hungry. Bipolar 0-100 point VAS included sad/happy, anxious/relaxed,
jittery/calm, bad/good, paranoid/self-assured, and fearful/unafraid.
Neurocognitive assessments assessed attention and concentration, learning and
memory, and fine motor speed.

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 A 30% reduction in pain was achieved in 61% of subjects who received the
3.53% THC marijuana, in 57% of subjects who received the 1.29% THC
marijuana and in 26% of subjects who received the placebo marijuana (p=0.002
for placebo vs. 3.53% THC, p=0.007 for placebo vs 1.29% THC; p>0.05 1.29%
THC vs. 3.53% THC). Both strengths of marijuana significantly decreased pain
intensity, unpleasantness, sharpness, and deepness on the NPS, as well as pain
ratings on the PGIC, compared to placebo. These effects on pain were maximal
with cumulative dosing over the course of the study session, with maximal effects
at 180 minutes. There were no effects of marijuana compared to placebo on
measures of allodynia or thermal pain. Subjects correctly identified the study
treatment 63% of the time for placebo, 61% of the time for 1.29% THC, and 89%
of the time for 3.53% THC.
On subjective measures, marijuana produced dose-dependent increases compared
to placebo on ratings for: any drug effect, good drug effect, drug liking, high,
stoned, sedated, confused, and hungry. Both strengths of marijuana produced
similar increases in drunk or impaired compared to placebo. In contrast, desire
for drug was rated as higher for the 1.29% THC marijuana compared to the 3.53%
THC marijuana. There were no changes compared to placebo for bad effect,
nauseous, anxiety, feeling down or any of the bipolar mood assessments. There
was dose-dependent impairment on learning and memory from marijuana
compared to placebo, but similar effects between the two strengths of marijuana
on attention.
The authors conclude that vaporization of relatively low doses of marijuana can
produce improvements in analgesia in neuropathic pain patients, especially when
patients are allowed to titrate their exposure. However, this individualization of
doses may account for the general lack of difference between the two strengths of
marijuana. No data were presented regarding the total amount of THC consumed
by each subject, so it is difficult to determine a proper dose-response evaluation.
Additional limitations of this study are the inclusion of subjects with many forms
of neuropathic pain and maintenance of subjects on other analgesic medication
while being tested with marijuana. These limitations make it difficult to conclude
that marijuana has analgesic properties on its own. It is also difficult to determine
if any particular subset of neuropathic pain conditions would benefit specifically
from marijuana administration. However, the study produced positive results
suggesting that marijuana should be studied further as an adjunct treatment for
uncontrolled neuropathic pain.
3.2 Appetite Stimulation in HIV
Two randomized, double-blind, placebo-controlled Phase 2 studies examined the
effects of smoked marijuana on appetite in HIV-positive subjects (Haney et al.,
2005; Haney et al., 2007). Table 2 of the Appendix summarizes both studies.

85

 The first study, conducted by Haney et al. (2005) is entitled, “Dronabinol and
marijuana in HIV+ marijuana smokers: acute effects on caloric intake and mood”.
The subjects were 30 HIV-positive patients who were maintained on two
antiretroviral medications and either had clinically significant decreases in lean
muscle mass34 (low-BIA group, n = 15) or normal lean muscle mass (normal-BIA
group, n = 15). All subjects had a history of smoking marijuana at least twice
weekly for 4 weeks prior to entry into the study. On average, individuals had
smoked 3 marijuana cigarettes per day, 5-6 times per week for 10-12 years.
Subjects participated in 8 sessions that tested the acute effects of 0, 10, 20, and 30
mg dronabinol oral capsules and marijuana cigarettes with 0%, 1.8%, 2.8%, and
3.9% THC concentration by weight, using a double-dummy design (with only one
active drug per session). The doses of dronabinol are higher than those doses
typically prescribed for appetite stimulation in order to help preserve the blinding.
There was a one-day washout period between test sessions.
Marijuana was administered using a standardized cued procedure: (1) “light the
cigarette” (30 seconds), (2) “prepare” (5 seconds), (3) “inhale” (5 seconds), (4)
“hold smoke in lungs” (10 seconds), and (5) “exhale.” Each subject smoked three
puffs in this manner, with a 40-second interval between each puff.
Caloric intake was used as a surrogate measure for weight gain. Subjects received
a box containing a variety of food and beverage items and were told to record
consumption of these items following that day’s administration of the test drug.
Subjective measures included 0-100 point VAS for feel drug effect, good effect,
bad effect, take drug again, drug liking, hungry, full, nauseated, thirsty, desire to
eat. Neurocognitive measures and vital signs were monitored.
The low BIA group consumed significantly more calories in the 1.8% and 3.9%
THC marijuana conditions (p<0.01) and the 10, 20, and 30 mg dronabinol
conditions (p<0.01) compared with the placebo condition. In contrast, in the
normal BIA group, neither marijuana nor dronabinol significantly affected caloric
intake. This lack of effect may be accountable, however, by the fact that this
group consumed approximately 200 calories more than the low BIA group under
baseline conditions.
Ratings of high and good drug effect were increased by all drug treatments in both
the low-BIA and normal-BIA groups, except in response to the 10 mg dose of
dronabinol. The 3.9% THC marijuana increased ratings of good drug effect, drug
liking and desire to smoke again compared with placebo. Ratings of sedation
were increased in both groups by 10 and 30 mg dronabinol, and in the normal
BIA group by the 2.8% THC marijuana. Ratings of stimulation were increased in
the normal BIA group by 2.8% and 3.9% THC marijuana and by 20 mg
34

Lean muscle mass was assessed using bioelectrical impedance analysis (BIA). The low-BIA group was
classified with having <90% BIA, and the normal-BIA group was classified with having >90% BIA.

86

 dronabinol. Increases in ratings of forgetfulness, withdrawn, dreaming, clumsy,
heavy limbs, heart pounding, jittery, and decreases in ratings of energetic, social,
and talkative were reported in the normal BIA group with 30 mg dronabinol.
There were no significant changes in vital signs or performance on neurocognitive
measures in response to marijuana. Notably, the time course of subjective effects
peaked quickly and declined thereafter for smoked marijuana, while oral
dronabinol responses took longer to peak and persisted longer. Additionally,
marijuana but not dronabinol produced dry mouth and thirst.
In general, AEs reported in this study were low in both drug conditions for both
subject groups. In the low BIA group, nausea was reported by one subject in both
the 10 and 20 mg dronabinol conditions, while an uncomfortable level of
intoxication was produced by the 30 mg dose in two subjects. There were no AEs
reported in this group following marijuana at any dose. In the normal BIA group,
the 30 mg dose of dronabinol produced an uncomfortable level of intoxication in
three subjects and headache in one subject, while the 3.9% marijuana produced
diarrhea in one subject.
The authors conclude that smoked marijuana can acutely increase caloric intake in
low BIA subjects without significant cognitive impairment. However, it is
possible that the low degree of cognitive impairment reported in this study may
reflect the development of tolerance to cannabinoids in this patient population,
since all individuals had current histories of chronic marijuana use. Additional
limitations in this study include not utilizing actual weight gain as a primary
measure. However, the study produced positive results suggesting that marijuana
should be studied further as a treatment for appetite stimulation in HIV patients.
A second study conducted by Haney et al. (2007) is entitled, “Dronabinol and
marijuana in HIV-positive marijuana smokers: Caloric intake, mood, and sleep”.
The design of this study was nearly identical to the one conducted by this
laboratory in 2005 (see above), but there was no stratification of subjects by BIA.
The subjects were 10 HIV-positive patients who were maintained on two
antiretroviral medications and had a history of smoking marijuana at least twice
weekly for 4 weeks prior to entry into the study. On average, individuals had
smoked 3 marijuana cigarettes per day, 5 times per week for 19 years.
Subjects participated in 8 sessions that tested the acute effects of 0, 5 and 10 mg
dronabinol oral capsules and marijuana cigarettes with 0, 2.0% and 3.9% THC
concentration by weight, using a double-dummy design (with 4 sessions involving
only one active drug and 4 interspersed placebo sessions). Both drug and placebo
sessions lasted for 4 days each, with active drug administration occurring 4 times
per day (every 4 hours). Testing occurred in two 16-day inpatient stays. In the
intervening outpatient period, subjects were allowed to smoke marijuana prior to
re-entry to the study unit for the second inpatient stay.

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 Marijuana was administered using a standardized cued procedure: (1) “light the
cigarette” (30 seconds), (2) “prepare” (5 seconds), (3) “inhale” (5 seconds), (4)
“hold smoke in lungs” (10 seconds), and (5) “exhale.” Each subject smoked three
puffs in this manner, with a 40-second interval between each puff.
Caloric intake was used as a surrogate measure for weight gain, but subjects were
also weighed throughout the study (a measure which was not collected in the
2005 study by this group). Subjects received a box containing a variety of food
and beverage items and were told to record consumption of these items following
that day’s administration of the test drug. Subjective measures included 0-100
point VAS for drug effect, good effect, bad effect, take drug again, drug liking,
hungry, full, nauseated, thirsty, desire to eat. Neurocognitive measures and vital
signs were monitored. Sleep was assessed using both the Nightcap sleep
monitoring system and selected VAS measures related to sleep.
Both 5 and 10 mg dronabinol (p < 0.008) and 2.0% and 3.9% THC marijuana (p <
0.01) dose-dependently increased caloric intake compared with placebo. This
increase was generally accomplished through increases in incidents of eating,
rather than an increase in the calories consumed in each incident. Subjects also
gained similar amounts of weight after the highest dose of each cannabinoid
treatment: 1.2 kg (2.6 lbs) after 4 days of 10 mg dronabinol, and 1.1 kg (2.4 lbs)
after 4 days of 3.9% THC marijuana. The 3.9% THC marijuana dose also
increased the desire to eat and ratings of hunger.
Ratings of good drug effect, high, drug liking, and desire to smoke again were
significantly increased by 10 mg dronabinol and 2.0% and 3.9% THC marijuana
doses compared to placebo. Both marijuana doses increased ratings of stimulated,
friendly, and self-confident. The 10 mg dose of dronabinol increased ratings of
concentration impairment, and the 2.0% THC marijuana dose increased ratings of
anxious. Dry mouth was induced by 10 mg dronabinol (10 mg) and 2.0% THC
marijuana. There were no changes in neurocognitive performance or objective
sleep measures from administration of either cannabinoid. However, 3.9% THC
marijuana increased subjective ratings of sleep.
The authors conclude that both dronabinol and smoked marijuana increase caloric
intake and produce weight gain in HIV-positive patients. However, it is possible
that the low degree of cognitive impairment reported in this study may reflect the
development of tolerance to cannabinoids in this subject population, since all
individuals had current histories of chronic marijuana use. This study produced
positive results suggesting that marijuana should be studied further as a treatment
for appetite stimulation in HIV patients.
3.3 Spasticity in Multiple Sclerosis
Only one randomized, double-blind, placebo-controlled Phase 2 study examined
the effects of smoked marijuana on spasticity in MS.
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 This study was conducted by Corey-Bloom et al. (2012) and is entitled, “Smoked
cannabis for spasticity in multiple sclerosis: a randomized, placebo-controlled
trial”. The subjects were 30 patients with MS-associated spasticity and had
moderate increase in tone (score ≥ 3 points on the modified Ashworth scale).
Participants were allowed to continue other MS medications, with the exception
of benzodiazepines. Eighty percent of subjects had a history of marijuana use and
33% had used marijuana within the previous year.
Subjects participated in two 3-day test sessions, with an 11 day washout period.
During each test session they smoked a 4.0% THC marijuana cigarette once per
day or a placebo cigarette once per day. Smoking occurred through a
standardized cued-puff procedure: (1) inhalation for 5 seconds, (2) breath-hold
and exhalation for 10 seconds, (3) pause between puffs for 45 seconds. Subjects
completed an average of four puffs per cigarette.
The primary outcome measure was change in spasticity on the modified Ashworth
scale. Additionally, subjects were assessed using a VAS for pain, a timed walk,
and cognitive tests (Paced Auditory Serial Addition Test) and AEs.
Treatment with 4.0% THC marijuana reduced subject scores on the modified
Ashworth scale by an average of 2.74 points more than placebo (p < 0.0001) and
reduced VAS pain scores compared to placebo (p = 0.008). Scores on the
cognitive measure decreased by 8.7 points more than placebo (p = 0.003).
However, marijuana did not affect scores for the timed walk compared to placebo.
Marijuana increased rating of feeling high compared to placebo.
7 subjects did not complete the study due to adverse events (two subjects felt
uncomfortably “high”, two had dizziness and one had fatigue). Of those 7
subjects who withdrew, 5 had little or no previous experience with marijuana.
When the data were re-analyzed to include these drop-out subjects, with the
presumption they did not have a positive response to treatment, the effect of
marijuana was still significant on spasticity.
The authors conclude that smoked marijuana had usefulness in reducing pain and
spasticity associated with MS. It is concerning that marijuana-naïve subjects
dropped out of the study because they were unable to tolerate the psychiatric AEs
induced by marijuana. The authors suggest that future studies should examine
whether different doses can result in similar beneficial effects with less cognitive
impact. However, the current study produced positive results suggesting that
marijuana should be studied further as an adjunct treatment for spasticity in MS
patients.
3.4 Asthma
Tashkin et al. (1974) examined bronchodilation in 10 subjects with bronchial asthma in
the study entitled, “Acute Effects of Smoked Marijuana and Oral Δ989

 Tetrahydrocannabinol on Specific Airway Conductance in Asthmatic Subjects”. The
study was a double-blind, placebo-controlled, crossover design. All subjects were
clinically stable at the time of the study; four subjects were symptom free, and six
subjects had chronic symptoms of mild to moderate severity. Subjects were tested with
0.25ml of isoproterenol HCl prior to the study to ensure they responded to bronchodilator
medications. Subjects were not allowed to take bronchodilator medication within 8 hours
prior to the study. Previous experience with marijuana was not required for participation
in the study, but 7 of the 10 subjects reported previous use of marijuana at a rate of less
than 1 marijuana cigarette per month. No subjects reported marijuana use within 7 days
of the study.
The study consisted of four test sessions with an interval of at least 48 hours between
sessions. On two test sessions subjects smoked 7 mg/kg of body weight of either
marijuana, with 2% THC concentration by weight, or placebo marijuana. During the
other two test sessions, subjects ingested capsules with either 15mg of synthetic THC or
placebo. Marijuana was administered using a uniform smoking technique: subjects
inhaled deeply for 2-4 seconds, held smoke in lungs for 15 seconds, and resumed normal
breathing for approximately 5 seconds. The author did not provide a description of the
number of puffs taken at any smoking session. The authors state that the smoking
procedure was repeated until the cigarette was consumed, which took approximately 10
minutes.
The outcome measure used was specific airway conductance (SGaw), as calculated using
measurements of thoracic gas volume (TGV) and airway resistance (Raw) using a
variable-pressure body plethysmograph. Additionally, an assessment of degree of
intoxication was administered only to those subjects reporting previous marijuana use.
This assessment consisted of subjects rating “how ‘high’ they felt” on a scale of 0-7, 7
representing “the ‘highest’ they had ever felt after smoking marijuana”.
Marijuana produced a significant increase of 33-48% in average SGaw compared to both
baseline and placebo (P < 0.05). This significant increase in SGaw lasted for at least 2
hours after administration. The average TGV significantly decreased by 4-13%
compared to baseline and placebo (P < 0.05). The author stated that all subjects reported
feelings of intoxication after marijuana administration.
The authors conclude that marijuana produced bronchodilation in clinically stable
asthmatic subjects with minimal to moderate bronchospasms. Study limitations include:
inclusion of subjects with varying severity of asthmatic symptoms, use of SGaw to
measure lung responses to marijuana administration, and administration of smoke to
asthmatic subjects. Smoke delivers a number of harmful substances and is not an optimal
delivery symptom, especially for asthmatic patients. FEV1 via spirometry is the gold
standard to assess changes in lung function, pre and post asthma treatment, by
pharmacotherapy. SGaw has been shown to be a valid tool in bronchoconstriction lung
assessment; however, since the FEV1 method was not utilized, it is unclear whether these
results would correlate if the FEV1 method had been employed.
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 3.5 Glaucoma
Two randomized, double-blind, placebo-controlled Phase 2 clinical studies
examined smoked marijuana in glaucoma (Crawford and Merritt, 1979;
Merritt et al., 1980). In both studies, intraocular pressure (IOP) was significantly
reduced 30 minutes after smoking marijuana. Maximal effects occurred 60-90
minutes after smoking, with IOP returning to baseline within 3-4 hours. These
two studies were included in the 1999 IOM report on the medical uses of
marijuana. Because our independent analysis of these studies concurred with the
conclusions from the 1999 IOM report, these studies will not be discussed in
further detail in this review. No recent studies have been conducted examining
the effect of inhaled marijuana on IOP in glaucoma patients. This lack of recent
studies may be attributed to the conclusions made in the 1999 IOM report that
while cannabinoids can reduce intraocular pressure (IOP), the therapeutic effects
require high doses that produce short-lasting responses, with a high degree of
AEs. This high degree of AEs means that the potential harmful effects of chronic
marijuana smoking may outweigh its modest benefits in the treatment of
glaucoma.
3.6 Conclusions
Of the eleven randomized, double-blind, placebo-controlled Phase 2 clinical
studies that met the criteria for review (see Sections 2.2 and 2.3), ten studies
administered marijuana through smoking, while one study utilized marijuana
vaporization. In these eleven studies, there were five different therapeutic
indications: five examined chronic neuropathic pain, two examined appetite
stimulation in HIV patients, two examined glaucoma, one examined spasticity in
MS, and one examined asthma.
There are limited conclusions that can be drawn from the data in these published studies
evaluating marijuana for the treatment of different therapeutic indications. The analysis
relied on published studies, thus information available about protocols, procedures, and
results were limited to documents published and widely available in the public domain.
The published studies on medical marijuana are effectively proof-of-concept studies.
Proof-of-concept studies provide preliminary evidence on a proposed hypothesis
regarding a drug’s effect. For drugs under development, the effect often relates to a
short-term clinical outcome being investigated. Proof-of-concept studies serve as the link
between preclinical studies and dose ranging clinical studies. Therefore, proof-ofconcept studies are not sufficient to demonstrate efficacy of a drug because they provide
only preliminary information about the effects of a drug. Although these studies do not
provide evidence that marijuana is effective in treating a specific, recognized disorder,
these studies do support future larger well-controlled studies to assess the safety and
efficacy of marijuana for a specific medical indication. Overall, the conclusions below
are preliminary, based on very limited evidence.
3.6.1 Conclusions for Chronic Neuropathic Pain
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 In subjects with chronic neuropathic pain who are refractory to other pain
treatments, five proof-of-concept studies produced positive results regarding the
use of smoked marijuana for analgesia. However, the subjects in these studies
continued to use their current analgesic drug regime, and thus no conclusions can
be made regarding the potential efficacy of marijuana for neuropathic pain in
patients not taking other analgesic drugs. Subjects also had numerous forms of
neuropathic pain, making it difficult to identify whether a specific set of
symptoms might be more responsive to the effects of marijuana. It is especially
concerning that some marijuana-naïve subjects had intolerable psychiatric
responses to marijuana exposure at analgesic doses.
3.6.2 Conclusions for Appetite Stimulation in HIV
In subjects who were HIV-positive, two proof-of-concept studies produced
positive results with the use of both dronabinol and smoked marijuana to increase
caloric intake and produce weight gain in HIV-positive patients. However, the
amount of THC in the marijuana tested in these studies is four times greater than
the dose of dronabinol typically tested for appetite stimulation (10 mg vs. 2.5 mg;
Haney et al., 2005). Thus, it is possible that the low degree of AEs reported in
this study may reflect the development of tolerance to cannabinoids in this patient
population, since all individuals had current histories of chronic marijuana use.
Thus, individuals with little prior exposure to marijuana may not respond
similarly and may not be able to tolerate sufficient marijuana to produce appetite
stimulation.
3.6.3 Conclusions for Spasticity in MS
In subjects with MS, a proof of concept study produced positive results using
smoked marijuana as a treatment for pain and symptoms associated with
treatment-resistant spasticity. The subjects in this study continued to take their
current medication regiment, and thus no conclusions can be made regarding the
potential efficacy of marijuana when taken on its own. It is also concerning that
marijuana-naïve subjects dropped out of the study because they were unable to
tolerate the psychiatric AEs induced by marijuana. The authors suggest that
future studies should examine whether different doses can result in similar
beneficial effects with less cognitive impact.
3.6.4 Conclusions for Asthma
In subjects with clinically stable asthma, a proof of concept study produced positive
results of smoked marijuana producing bronchodilation. However, in this study
marijuana was administered at rest and not while experiencing bronchospasms.
Additionally, the administration of marijuana through smoking introduces harmful and
irritating substances to the subject, which is undesirable especially in asthmatic patients.
92

 Thus the results suggest marijuana may have bronchodilator effects, but it may also have
undesirable adverse effects in subjects with asthma.
3.6.5 Conclusions for Glaucoma
As noted in Sections 3.5, the two studies that evaluated smoked marijuana for
glaucoma were conducted decades ago, and they have been thoroughly evaluated
in the 1999 IOM report. The 1999 IOM report concludes that while the studies
with marijuana showed positive results for reduction in IOP, the effect is shortlasting, requires a high dose, and is associated with many AEs. Thus, the
potential harmful effects may outweigh any modest benefit of marijuana for this
condition. We agree with the conclusions drawn in the 1999 IOM report.
3.7 Design Challenges for Future Studies
The positive results reported by the studies discussed in this review support the
conduct of more rigorous studies in the future. This section discusses
methodological challenges that have occurred in clinical studies with smoked
marijuana. These design issues should be addressed when larger-scale clinical
studies are conducted to ensure that valid scientific data are generated in studies
evaluating marijuana’s safety and efficacy for a particular therapeutic use.
3.7.1 Sample Size
The ability for results from a clinical study to be generalized to a broader population is
reliant on having a sufficiently large study sample size. However, as noted above, all of
the 11 studies reviewed in this document were early Phase 2 proof of concept studies for
efficacy and safety. Thus, the sample sizes used in these studies were inherently small,
ranging from 10 subjects per treatment group (Tashkin et al., 1974; Haney et al., 2007) to
25 subjects per treatment group (Abrams et al., 2007). These sample sizes are
statistically inadequate to support a showing of safety or efficacy. FDA’s
recommendations about sample sizes for clinical trials can be found in the Guidance for
Industry: E9 Statistical Principles for Clinical Trials (1998).35 For example, “the
number of subjects in a clinical trial should always be large enough to provide a reliable
answer to the questions addressed. This number is usually determined by the primary
objective of the trial. The method by which the sample size is calculated should be given
in the protocol, together with the estimates of any quantities used in the calculations
(such as variances, mean values, response rates, event rates, difference to be detected).”
(pg. 21). Other clinical FDA Guidance for Industry36 may also contain recommendations
regarding the appropriate number of subjects that should be investigated for a specific
medical indication.

35

The Guidance for Industry: E9 Statistical Principles for Clinical Trials can be found at:
www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm073137.pdf
36
Other Guidances for Industry can be found at:
www.fda.gov/Drugs/GuidanceComplianceRegulatory Information/Guidances/ ucm064981.htm

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 3.7.2 Marijuana Dose Standardization
Dose standardization is critical for any clinical study in order to ensure that each subject
receives a consistent exposure to the test drug. The Guidance for Industry: Botanical
Drug Products (2004) 37 provides specific information on the development of botanical
drug products. Specifically, this guidance includes information about the need for wellcharacterized and consistent chemistry for the botanical plant product and for consistent
and reliable dosing. Specifically for marijuana studies, dose standardization is important
because if marijuana leads to plasma levels of cannabinoids that are significantly
different between subjects, this variation may lead to differences in therapeutic
responsivity or in the prevalence of psychiatric AEs.
In most marijuana studies discussed in this review, investigators use a
standardized cued smoking procedure. In this procedure, a subject is instructed to
inhale marijuana smoke for 5 seconds, hold the smoke in the lungs for 10 seconds,
exhale and breathe normally for 40 seconds. This process is repeated to obtain
the desired dose of the drug. However, this procedure may not lead to equivalent
exposure to marijuana and its constituent cannabinoids, based on several factors:
 Intentional or unintentional differences in the depth of inhalation may
change the amount of smoke in the subject’s lungs.
 Smoking results in loss from side stream smoke, such that the entire dose
is not delivered to the subject.
 There may be differences in THC concentration along the length of a
marijuana cigarette. According to Tashkin et al. (1991), the area of the
cigarette closest to the mouth tends to accumulate a higher concentration
of THC, but this section of the cigarette is not smoked during a study.
For example, Wilsey et al. (2008) used this standardized smoking procedure. The
reported mean (range) of marijuana cigarettes consumed was 550 mg (200830mg) for the low strength marijuana (3.5% THC) and 490 mg (270-870mg) for
the high strength marijuana (7% THC). This wide range of amounts of marijuana
cigarette smoked by the individual subjects, even with standardized smoking
procedure and controlled number of puffs, supports the issues with delivering
consistent doses with smoke marijuana.
In other marijuana studies that do not use a cued smoking procedure, subjects are
simply told to smoke the marijuana cigarette over a specific amount of time
(usually 10 minutes) without further instruction (Crawford and Merritt, 1979;
Merritt et al., 1980; Ellis et al., 2009). The use of a nonstandardized procedure
may lead to non-equivalent exposures to marijuana and its constituent
37

The Guidance for Industry: Botanical Drug Products can be found at:
http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm070491.
pdf.

94

 cannabinoids between subjects because of additional factors that are not listed
above, such as:
 Differences in absorption and drug response if subjects (especially
marijuana-naïve ones) are not instructed to hold marijuana smoke in their
lungs for a certain period of time.
 Prolonged periods between puffs may increase loss to side stream smoke.
 Subjects may attempt to smoke the marijuana cigarette in the way they
would smoke a tobacco cigarette, which relies primarily on short, shallow
puffs.
In both standardized and non-standardized smoking procedures, subjects may
seek to control the dose of THC through self-titration (Crawford and Merritt,
1979; Merritt et al., 1980; Tashkin et al., 1974; Abrams et al., 2007; Ellis et al.,
2009). Self-titration involves an individual moderating the amount of marijuana
smoke inhaled over time in order to obtain a preferred level of psychoactive or
clinical response. The ability of an individual to self-titrate by smoking is one
reason given by advocates of “medical marijuana” in support of smoking of
marijuana rather than through its ingestion via edibles. However, for research
purposes, self-titration interferes with the ability to maintain consistent dosing
levels between subjects, and thus, valid comparisons between study groups.
All of these factors can make the exact dose of cannabinoids received by a subject
in a marijuana study difficult to determine with accuracy. Testing whether
plasma levels of THC or other cannabinoids are similar between subjects
following the smoking procedure would establish whether the procedure is
producing appropriate results. Additionally, studies could be conducted to
determine if vaporization can be used to deliver consistent doses of cannabinoids
from marijuana plant material. Specifically, vaporization devices that involve the
collection of vapors in an enclosed bag or chamber may help with delivery of
consistent doses of marijuana. Thus, more information could be collected on
whether vaporization is comparable to or different than smoking in terms of
producing similar plasma levels of THC in subjects using identical marijuana
plant material.
3.7.3 Acute vs. Chronic Therapeutic Marijuana Use
The studies that were reviewed administered the drug for short durations lasting
no longer than 5 days (Abrams et al., 2007; Ellis et al., 2009; Ware et al., 2010).
Thus all studies examined the short-term effect of marijuana administration for
therapeutic purposes. However, many of the medical conditions that have been
studied are persistent or expected to last the rest of a patient’s life. Therefore,
data on chronic exposure to smoked marijuana in clinical studies is needed. In
this way, more information will be available regarding whether tolerance,
95

 physical dependence, or specific adverse events develop over the course of time
with continuing use of therapeutic marijuana.
3.7.4 Smoking as a Route of Administration
As has been pointed out by the IOM and other groups, smoking is not an optimum
route of administration for marijuana-derived therapeutic drug products, primarily
because introducing the smoke from a burnt botanical substance into the lungs of
individuals with a disease state is not recommended when their bodies may be
physically compromised. The 1999 IOM report on medicinal uses of marijuana
noted that alternative delivery methods offering the same ability of dose titration
as smoking marijuana will be beneficial and may limit some of the possible longterm health consequences of smoking marijuana. The primary alternative to
smoked marijuana is vaporization, which can reduce exposure to combusted plant
material containing cannabinoids. The only study to use vaporization as the
delivery method was Wilsey et al. (2013). The results from Wilsey et al. (2013)
showed a similar effect of decreased pain as seen in the other studies using
smoking as the delivery method (Ware et al., 2010; Wilsey et al., 2008). This
similar effect of decrease pain supports vaporization as a possibly viable route to
administer marijuana in research, while potentially limiting the risks associated
with smoking.
3.7.5 Difficulty in Blinding of Drug Conditions
An adequate and well-controlled clinical study involves double-blinding, where
both the subjects and the investigators are unable to tell the difference between
the test treatments (typically consisting of at least a test drug and placebo) when
they are administered. All of the studies reviewed in this document administered
study treatments under double-blind conditions and thus were considered to have
an appropriate study design.
However, even under the most rigorous experimental conditions, blinding can be
difficult in studies with smoked marijuana because the rapid onset of
psychoactive effects readily distinguishes active from placebo marijuana. The
presence of psychoactive effects also occurs with other drugs. However, most
other drugs have a similar psychoactive effect with substances with similar
mechanisms of actions. These substances can be used as positive controls to help
maintain blinding to the active drug being tested. Marijuana on the other hand,
has a unique set of psychoactive effects which makes the use of appropriate
positive controls difficult (Barrett et al., 1995). However, two studies did use
Dronabinol as a positive control drug to help maintain blinding (Haney et al.,
2005; Haney et al., 2007).
When blinding is done using only placebo marijuana, the ability to distinguish
active from placebo marijuana may lead to expectation bias and an alteration in
perceived responsivity to the therapeutic outcome measures. With marijuanaexperienced subjects, for example, there may be an early recognition of the more
96

 subtle cannabinoid effects that can serve as a harbinger of stronger effects, which
is less likely to occur with marijuana-naïve subjects. To reduce this possibility,
investigators have tested doses of marijuana other than the one they were
interested in experimentally to maintain the blind (Ware et al., 2010).
Blinding can also be compromised by differences in the appearance of marijuana
plant material based on THC concentration. Marijuana with higher
concentrations of THC tends to be heavier and seemingly darker, with more “tarlike” substance. Subjects who have experience with marijuana have reported
being able to identify marijuana from placebo cigarettes by sight alone when the
plant material in a cigarette was visible (Tashkin et al., 1974; Ware et al., 2010).
Thus, to maintain a double-blind design, many studies obscure the appearance of
plant material by closing both ends of the marijuana cigarette and placing it in in
an opaque plastic tube.
While none of these methods to secure blinding may be completely effective, it is
important to reduce bias as much as possible to produce consistent results
between subjects under the same experimental conditions.
3.7.6 Prior Marijuana Experience
Marijuana use histories in test subjects may influence outcomes, related to both
therapeutic responsivity and psychiatric AEs. Marijuana-naïve subjects may also
experience a marijuana drug product as so aversive that they would not want to
use the drug product. Thus, subjects’ prior experience with marijuana may affect
the conduct and results of studies.
Most of the studies reviewed in this document required that subjects have a
history of marijuana use (see tables in Appendix that describe specific
requirements for each study). However, in studies published in the scientific
literature, the full inclusion criteria with regard to specific amount of experience
with marijuana may not be provided. For those studies that do provide inclusion
criteria, acceptable experience with marijuana can range from once in a lifetime to
use multiple times a day.
The varying histories of use might affect everything from scores on adverse event
measures, safety measures, or efficacy measures. Additionally, varying amounts
of experience can impact cognitive effect measures assessed during acute
administration studies. For instance, Schreiner and Dunn (2012) contend
cognitive deficits in heavy marijuana users continue for approximately 28 days
after cessation of smoking. Studies requiring less than a month of abstinence
prior to the study may still see residual effects of heavy use at baseline and after
placebo marijuana administration, thus showing no significant effects on
cognitive measures. However, these same measurements in occasional or naïve
marijuana users may demonstrate a significant effect after acute marijuana
administration. Therefore, the amount of experience and the duration of
abstinence of marijuana use are important to keep in mind when analyzing results
97

 for cognitive and other adverse event measures. Lastly, a study population with
previous experience with marijuana may underreport the incidence and severity of
adverse events. Because most studies used subjects with prior marijuana
experience, we are limited in our ability to generalize the results, especially for
safety measures, to marijuana naïve populations.
Five of 11 studies reviewed in this document included both marijuana-naïve and
marijuana-experienced subjects (Corey-Bloom et al., 2012; Ellis et al., 2009;
Ware et al., 2010; Merritt et al., 1980; Tashkin et al., 1974). Since the number of
marijuana-naïve subjects in these studies was low, it was not possible to conduct a
separate analysis compared to experienced users. However, systematically
evaluating the effect of marijuana experience on study outcomes is important,
since many patients who might use a marijuana product for a therapeutic use will
be marijuana-naïve.
Research shows that marijuana-experienced subjects have a higher ability to
tolerate stronger doses of oral dronabinol than marijuana-naïve subjects (Haney et
al., 2005). Possibly, this increased tolerance is also the case when subjects smoke
or vaporize marijuana. Thus, studies could be conducted that investigate the role
of marijuana experience in determining tolerability of and responses to a variety
of THC concentrations in marijuana.
3.7.7 Inclusion and Exclusion Criteria
For safety reasons, all clinical studies have inclusion and exclusion criteria that
restrict the participation of individuals with certain medical conditions. For
studies that test marijuana, these criteria may be based on risks associated with
exposure to smoked material and the effects of THC. Thus, most studies
investigating marijuana require that subjects qualify for the study based on
restrictive symptom criteria such that individuals do not have other symptoms that
may be known to interact poorly with cannabinoids.
Similarly, clinical studies with marijuana typically exclude individuals with
cardiac or pulmonary problems, as well as psychiatric disorders. These exclusion
criteria are based on the well-known effects of marijuana smoke to produce
increases in heart rate and blood pressure, lung irritation, and the exacerbation of
psychiatric disturbances in vulnerable individuals. Although these criteria are
medically reasonable for research protocols, it is likely that future marijuana
products will be used in patients who have cardiac, pulmonary or psychiatric
conditions. Thus, individuals with these conditions should be evaluated,
whenever possible.
Additionally, all studies reviewed in this document allowed the subjects to
continue taking their current regimen of medications. Thus all results evaluated
marijuana as an adjunct treatment for each therapeutic indication.
3.7.8 Number of Female Subjects
98

 A common problem in clinical research is the limited number of females who
participate in the studies. This problem is present in the 11 studies reviewed in
this document, in which one study did not include any female subjects (Ellis et al.,
2009), and three studies had a low percentage of female subjects (Abrams et al.,
2007; Haney et al., 2005; Haney et al., 2007). However, each of these four
studies investigated an HIV-positive patient population, where there may have
been a larger male population pool from which to recruit compared to females.
Since there is some evidence that the density of CB1 receptors in the brain may
vary between males and females (Crane et al., 2012), there may be differing
therapeutic or subjective responsivity to marijuana. Studies using a study
population that is equal parts male and female may show whether and how the
effects of marijuana differ between male and female subjects.
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102

 Appendix (Tables)
Table 1: Randomized, controlled, double-blind trials examining smoked marijuana in treatment of neuropathic pain
Author &
Subjects (n)
Drugs
Study
Primary
Primary Outcome
Date
completed/randomized
Admin. Methods
Type
Outcome
Measure Results
Indication
Subject characteristics
Duration
Measure
Abrams et al.
Marijuana Group: 25/27
NIDA marijuana,
Parallel
VAS daily -52% of the marijuana
(2007)
22 males
smoked
Group
pain score group showed >30%
5 females
0%, 3.65% THC
decrease in pain score
HIV-Sensory
5-day
compared to 24% of
Neuropathy;
Placebo Group: 25/28
Smoking Procedure:
treatment
placebo group.
Neuropathic
26 males
-signal light cued
period
-Marijuana group had
Pain
2 females
smoking of marijuana
significantly greater
cigarette with each
reduction in daily pain
Inclusion Criteria:
puff consisting of:
score than placebo
-documented HIV
1) 5s inhale smoke,
group.
-documented HIV-SN
2) 10s hold smoke in
-pain score ≥30mm VAS
lungs
-NNT=3.6
-prior marijuana use of six
3) 40s exhale and
or more times in lifetime
breath normally
4) repeat procedure for
Previous Marijuana
desired number of
Experience:
puffs
-marijuana group: 21
# of puffs not
current users
specified, only
-placebo group: 19 current
specified that subjects
users
smoked the entire
marijuana/placebo
Exclusion Criteria:
cigarette
-substance abuse
(including tobacco)
On 1st and last day of
-family history of
intervention period
neuropathy due to causes
BID.
not HIV related
For all other days TID
-use of isoniazid, dapsone,
or metronidazole within 8
weeks of enrollment
Ellis et al.
28/34
NIDA marijuana,
Crossover
Pain
-Pain reduction was
(2009)
28 males
smoked
magnitude significantly greater
0%, 1%, 2%, 4%, 6%,
Doseon DDS
after marijuana
HIV Sensory
Inclusion Criteria:
8% THC
titration (on
compared to placebo.
Neuropathy;
-documented HIV
1st day)
Neuropathic
-documented neuropathic
Smoking Procedures:

1

Adverse events/AEs

-Rating for adverse events of
anxiety, sedation, disorientation,
confusion, and dizziness were
significantly higher in the
marijuana group compared to
placebo group.
-Marijuana and placebo groups
showed a reduction in total mood
disturbance on POMS.
AEs:
-1 grade 3 dizziness in marijuana
group
-2 grade 3 anxiety, 1 in each group.

-Mood disturbance, quality of life,
and psychical disability improved
for both marijuana and placebo.
-Moderate to severe adverse events
were more common with
marijuana than placebo.

 Author &
Date
Indication
Pain

Subjects (n)
completed/randomized
Subject characteristics
pain refractory to ≥2
analgesics
-pain score ≥5 on pain
intensity subscale of DDS
Previous Marijuana
Experience:
-27 subjects had previous
experience
-63% of subjects had no
exposure for >1 year
before study

Wilsey et al.
(2008)
Neuropathic
pain; Various
Causes

Exclusion Criteria:
-current DSM-IV
substance abuse disorder
-lifetime history of
dependence on marijuana
-previous psychosis with or
intolerance to cannabinoids
-concurrent use of
approved cannabinoid
medications
-positive UDS for
cannabinoids during washin week
-serious medical conditions
that affect safety
-alcohol or drug
dependence within 12
months of study
32/38
20 males
18 females
Inclusion Criteria:
-CRPS type I, spinal cord

Drugs
Admin. Methods
- Verbally cued
smoking of marijuana
cigarette with each
puff consisting of:
1) 5s inhale smoke,
2) 10s hold smoke in
lungs
3) 40s exhale and
breath normally
4) repeat procedure for
desired number of
puffs
-unknown number of
puffs

Study
Type
Duration
2, 5-day
treatment
phase, with
2-week
washout
period

Primary
Outcome
Measure

Primary Outcome
Measure Results
-NNT=3.5

Smoking Procedure:
Verbally cued

-HIV disease parameters did not
differ for marijuana or placebo.
-Adverse events included:
concentration difficulties, fatigue,
sleepiness or sedation, increased
duration of sleep, reduced
salivation, and thirst. These
adverse events were more frequent
in marijuana compared to placebo.
Withdrawals for drug related
reasons:
-1 cannabis-naïve subject had
acute cannabis-induced psychosis
-1 subjects developed an
intractable smoking-related cough
during marijuana administration

QID

NIDA marijuana,
smoked
0%, 3.55%, 7% THC

Adverse events/AEs

Crossover
3, 6-hour
sessions,
with 3-day
between

104

VAS
spontaneo
us pain
intensity

-A significant decrease
in pain intensity for
both strengths of
marijuana compared to
placebo

-7% THC marijuana significantly
decreased functioning on
neurocognitive measures compared
to placebo.
-Subjective effects were greater for
7% THC marijuana than 3.55%

 Author &
Date
Indication

Subjects (n)
completed/randomized
Subject characteristics
injury, peripheral
neuropathy, or nerve
damage
-previous marijuana use
Previous Marijuana
Experience:
-median (range) time from
previous exposure: 1.7
years (31 days to 30 years)
-median (range) exposure
duration: 2 years (1 day to
22 years).

Ware et al.
(2010)
Post-traumatic
or
postsurgical
neuropathic
pain

Exclusion Criteria:
-no marijuana or
cannabinoid medication
use for 30 days prior to
study; confirmed by UDS
-severe depression
-history of schizophrenia or
bipolar depression
-uncontrolled hypertension,
cardiovascular disease, and
pulmonary disease
-active substance abuse
21/23
11 males
12 females
Inclusion Criteria:
-neuropathic pain for ≥ 3
months caused by trauma
or surgery
-allodynia and hyperalgesia
-pain score ˃4cm VAS
-no marijuana use for 1

Drugs
Admin. Methods
smoking of marijuana
cigarette with each
puff consisting of:
1) 5s inhale smoke,
2) 10s hold smoke in
lungs
3) 40s exhale and
breath normally
4) repeat procedure for
desired number of
puffs

Study
Type
Duration
sessions

Primary
Outcome
Measure

Crossover

Pain
intensity
on 11-item
NRS

Primary Outcome
Measure Results

Adverse events/AEs

THC marijuana with significantly
more ratings of good drug effect,
bad drug effect, feeling high,
feeling stoned, impaired, sedation,
confusion, and hunger compared to
placebo.

Cumulative dosing
procedure:
-escalate the number
of puffs from 2 to 4
puffs over 3 smoking
sessions with 1 hour
between sessions
TID

NIDA placebo;
Prairie Plant System
Inc. (Canada)
marijuana, smoked
0%, 2.5%, 6%, 9.4%
THC
(25 mg of
marijuana/placebo
plant material was
placed in opaque

4, 5-day
outpatient*
treatment
phase, with
9-day
washout
periods

105

-Average daily pain
intensity was
significantly lower
after 9.4% THC
compared to placebo.

-Anxiety and depression were
significantly improved with 9.4%
THC compared to placebo.
-No significant difference between
placebo and 9.4% THC for
subjective effects.
AEs:
-248 mild AEs were reported
-6 moderate AEs were reported: 2
fall, 1 increased pain, 1 numbness,

 Author &
Date
Indication

Subjects (n)
completed/randomized
Subject characteristics
year prior to study
-stable analgesic regimen
-normal liver and renal
function
Previous Marijuana
Experience:
-18 subjects had used
marijuana before

Wilsey et al.
(2013)
Neuropathic
Pain; Various
Causes

Exclusion Criteria:
-pain due to cancer or
nociceptive causes
-significant cardiac or
pulmonary disease
-current substance abuse or
dependence (including
marijuana)
-history of psychotic
disorders
-current suicidal ideations
36/39
28 males
11 females
Inclusion Criteria:
-CRPS type 1, thalamic
pain, spinal cord injury,
peripheral neuropathy,
radiculopathy, or nerve
injury
-previous marijuana use
Previous Marijuana
Experience:
- median (range) time from
last exposure prior to

Drugs
Admin. Methods

Study
Type
Duration

Primary
Outcome
Measure

Primary Outcome
Measure Results

gelatin capsules)

Adverse events/AEs

1 drowsiness, 1 pneumonia
-Most frequently reported drugrelated AEs for 9.4% THC:
headache, dry eyes, burning
sensation, dizziness, numbness,
and cough.

Smoking Procedures:
-1) Break one capsule
open and tip content
into the bowl of a
titanium pipe
2) light marijuana
material
3) 5s inhale smoke
4) 10s hold smoke in
lungs
5) Exhale
1 puff burned all 25
mg of plant material

Withdrawals for drug related
reason:
-1 subject had increased pain after
6% THC administration
-1 subject tested positive for
cannabinoids in urine test during
placebo treatment

TID
Intermediate doses
were used to help
maintain blinding
NIDA marijuana,
vaporized
0%, 1.29%, 3.53%
THC
Smoking Procedures:
- Verbally cued
inhalation of vaporized
material in the balloon
with each puff
consisting of:
1) 5s inhale vapors,
2) 10s hold vapors in
lungs
3) 40s exhale and
breath normally

Crossover
3, 6-hour
sessions,
with at
least 3 days
between
sessions

VAS
spontaneo
us pain
intensity

-Number of subjects
that showed a 30%
reduction in pain
intensity was
significantly greater for
both strengths of
marijuana compared to
placebo.
-Both strengths of
marijuana showed a
similar significant
decrease in pain
compared to placebo.
-NNT=3.2 for 1.29%
THC marijuana vs.

106

-Scores for feeling stoned, feeling
high, like the drug effect, feeling
sedated, and feeling confused were
significantly greater for 3.53%
THC marijuana compared to
1.29% THC marijuana, and for
both strengths of marijuana
compared to placebo.
-Scores for feeling drunk and
feeling impaired are significantly
greater in both strengths of
marijuana compared to placebo.
-Scores for desired more of the
drug were significantly greater for
1.29% THC marijuana compared
to placebo, with no significant

 Author &
Date
Indication

Subjects (n)
completed/randomized
Subject characteristics
screening: 9.6 years (1 day
to 45 years)
-16 current marijuana users
and 23 past users
-# smoked daily: 6
current users, 5 past users
-# used approx. once
every 2 weeks: 8 current
users, 6 past users
-# used once every 4
weeks or less: 2 current
users, 12 past users
Exclusion Criteria:
-no marijuana or
cannabinoid medication
use for 30 days prior to
study; confirmed by UDS
-severe depression
-suicidal ideations
-diagnoses of serious
mental illness
-uncontrolled hypertension,
cardiovascular disease, or
chronic pulmonary disease
-active substance abuse

Drugs
Admin. Methods

Study
Type
Duration

4) repeat procedure for
desired number of
puffs

Primary
Outcome
Measure

Primary Outcome
Measure Results
placebo.
-NNT=2.9 for 3.53%
THC marijuana vs.
placebo.

BID
Cumulative & Flexible
Dosing:
-1st drug admin.
consisted of 4 puffs
from balloon.
-Followed 2 hours
later by 2nd drug
admin.
-2nd drug admin.
consisted of 4 to 8
puffs from balloon;
number of puffs taken
was left up to the
subject so they could
self-titrate to their
target does, which
balanced desired
response and tolerance
levels.

Adverse events/AEs

difference seen for 3.53% THC
marijuana.
-3.53% THC marijuana had
significantly worse performance
than 1.29% THC marijuana for
learning and memory.
-Both strengths of marijuana
significantly reduced scores on
attention compared to placebo.

*Out-patient: subjects were given enough doses of marijuana/placebo to last the 5-day treatment phase, and then were sent home for the remainder of the treatment phase.
AE=Adverse Event; BID=drug administered two times per day; CRPS=complex regional pain syndrome; DDS= Descriptor Differential Scale; NIDA=National Institute of Drug
Abuse; NNT=Number Needed to Treat; NRS=Numeric Rating Scale; QID=drug administered four times per day; THC=delta-9-tetrahydrocannbinol; TID=drug administered three
times per day; UDS=urine drug screen; VAS=Visual Analog Scale.

107

 Table 2: Randomized, controlled, double-blind trials examining smoked marijuana in treatment of appetite stimulation in HIV/AIDS
Author &
Subjects (n)
Drugs
Study Type
Primary
Results
Adverse events/AEs
Date
completed/randomized Admin. Methods
Duration
Outcome
(summary)
Indication Subject characteristics
Measure
Haney et
Low-BIA: 15/17
NIDA marijuana,
Crossover
No primary
-In Low-BIA all
-Ratings of high and good drug effect
al. (2005)
12 males
smoked
outcome
dronabinol doses and
were significantly increased for all
3 females
0%, 1.8%, 2.8%,
8, 7-hour
measure is
1.8% and 3.9% THC
strengths of marijuana and all doses of
HIV+ with Normal-BIA: 15/18
3.9% THC
session, with at specified
marijuana significantly
dronabinol except 10mg dronabinol.
either
15 males
least 1 day
increased caloric intake -3.9% THC significantly increased ratings
normal
Dronabinol, oral
between
Related
compared with placebo. of dry mouth and thirsty compared to
muscle
Inclusion Criteria:
0, 10, 20, 30mg
sessions
outcome
placebo.
mass
-21-50 years of age
measure was
-Low-BIA group showed no significant
(Normal-prescribed at least 2
Double-dummy
caloric intake
adverse event ratings, and in the normalBIA) or
antiretroviral
drug admin.
BIA group the only significant adverse
clinically
medications
Procedures:
events in response to marijuana included:
significant -currently under the care
-only 1 active dose
diarrhea after 3.9% THC marijuana.
loss of
of a physician for HIV
per session
-Dronabinol had more incidences of
muscle
management
-one
adverse events at all doses compared to
mass
-medically and
dronabinol/placebo
marijuana.
(Low-BIA) psychiatrically stable
capsule followed 1
-smoke marijuana ≥
hour later by
2x/week for past 4 weeks marijuana/placebo
smoking
Previous Marijuana
Experience:
Smoking
-mean (SD) # of
Procedures:
days/week of marijuana
Verbally cued
use: Low-BIA= 6 (2);
smoking of
Normal-BIA=5 (2)
marijuana cigarette
-mean (SD) # marijuana
with each puff
cigarettes/day: Lowconsisting of:
BIA=3 (2); Normal1) 5s inhale
BIA=3 (1)
smoke,
-mean (SD) years of
2) 10s hold smoke
marijuana use: Lowin lungs
BIA=12.2 (8.3); Normal- 3) 40s exhale and
BIA=10.8 (2.6)
breath normally
4) repeat for 3
Exclusion Criteria:
puffs per smoking
-diagnosis of nutritional
session

108

 Author &
Date
Indication

Haney et
al. (2007)

Subjects (n)
completed/randomized
Subject characteristics
malabsorption, major
depression, dementia,
chronic diarrhea,
weakness, fever,
significant pulmonary
disease
-an opportunistic
infection within past 3
months
-obesity
-use of steroids within
past 3 weeks
-drug dependence
(excluding marijuana or
nicotine)
10
9 males
1 female

HIV+
Inclusion Criteria:
-21-50 years of age
-taking ≥ 2 antiretroviral
medications
-under the care of a
physician for HIV
management
-medically and
psychiatrically stable
-smoke marijuana ≥
2x/week for the past 4
weeks
Previous Marijuana
Experience:
-mean (SD) # of
days/week of marijuana
use: 4.6 (0.6)

Drugs
Admin. Methods

Study Type
Duration

Primary
Outcome
Measure

Results
(summary)

Adverse events/AEs

-Both strengths of
marijuana significantly
increased caloric intake
compared to placebo.
-3.9% THC marijuana
significantly increased
body weight compared
to placebo.

-Both strengths of marijuana significantly
increased ratings of: good drug effect,
high, mellow, stimulate, friendly, and
self-confident. Only 2% THC marijuana
significantly increased ratings of anxious.
-Both strengths of marijuana significantly
increased subjective measures for
satisfied sleep and estimated time of
sleep.

QD

NIDA marijuana,
smoked
0%, 2%, 3.9%
THC
Dronabinol, oral
0, 5, 10mg
Double-dummy
drug admin.
Procedures:
-only 1 active dose
per session
-one
dronabinol/placebo
capsule followed 1
hour later by
marijuana/placebo
smoking

Crossover
2, 16-day
treatment
phases, with 510 days
between
phases
Each 16-day
treatment
phase
consisted of 2,
4-day active
drug period
with 4-day
placebo period
between active
drug periods.

No primary
outcome
measure is
specified
Related
outcome
measures were
Caloric Intake
& Body
Weight

Smoking
Procedures:

109

 Author &
Date
Indication

Subjects (n)
completed/randomized
Subject characteristics
-mean (SD) # marijuana
cigarettes/day: 3.2 (0.8)
-mean (SD) years of
marijuana use: 18.6 (3.3)
Exclusion Criteria:
-diagnosis of nutritional
malabsorption, major
depression, dementia,
chronic diarrhea,
weakness, fever,
significant pulmonary
disease
-an opportunistic
infection within past 3
months
-obesity
-use of steroids within
past 3 weeks
-drug dependence
(excluding marijuana or
nicotine)

Drugs
Admin. Methods

Study Type
Duration

Primary
Outcome
Measure

Results
(summary)

Adverse events/AEs

Light cued
smoking of
marijuana cigarette
with each puff
consisting of:
1) 5s inhale
smoke,
2) 10s hold smoke
in lungs
3) 40s exhale and
breath normally
4) repeat for 3
puffs per smoking
session
QID

AE=Adverse Event; BIA=Bioelectric Impedance Analysis; NIDA=National Institute of Drug Abuse; QD=drug administered one time per day; QID=drug
administered four times per day; THC=delta-9-tetrahydrocannbinol

110

 Table 3: Randomized, controlled, double-blind trails examining smoked marijuana in treatment of spasticity in Multiple Sclerosis
Author &
Subjects (n)
Drugs
Study Type
Primary
Primary Outcome Measure
Adverse events/AEs
Date
completed/randomized
Admin. Methods
Duration
Outcome
Results
Indication Subject characteristics
Measure
Corey30/37
NIDA marijuana,
Crossover
Spasticity
-Smoking marijuana
-Marijuana reduced scores on
Bloom et al. 11 males
smoked
on the
significantly reduced spasticity
cognitive measure compared to
(2012)
19 females
0%, 4% THC
2, 3-day
Modified
scores compared to placebo
placebo.
treatment
Ashworth
-Marijuana significantly increased
Multiple
Inclusion Criteria:
Smoking Procedure:
periods, with Scale
perceptions of “highness”
Sclerosis;
-documented MS
smoking of
11 day
compared to placebo
Spasticity
-spasticity
marijuana cigarette
washout
-moderate increase in
with each puff
period
Withdrawals for drug-related
tone (score ≥ 3 on
consisting of:
reasons:
modified Ashworth scale 1) 5s inhale smoke,
-2 subjects felt uncomfortably
2) 10s hold smoke in
high
Previous Marijuana
lungs
-2 dizziness
Experience:
3) 45s exhale and
-1 fatigue
-24 subjects had previous breath normally
exposure to marijuana
4) repeat for an
-10 subjects used
average of 4 puffs
marijuana within the year per smoking session
Exclusion Criteria:
-no marijuana smoking
for ≤1 month prior to
screening
-psychiatric disorder
(other than depression)
-history of substance use
-substantial neurological
disease other than MS
-severe or unstable
medical illnesses
-known pulmonary
disorders
-using high dose narcotic
medication for pain
-using benzodiazepines
to control spasticity

QD

AE=Adverse Event; MS= Multiple Sclerosis; NIDA=National Institute of Drug Abuse; QD=drug administered one time per day; THC=delta-9-tetrahydrocannbinol

111

 Table 4: Randomized, controlled, double-blind trails examining smoked marijuana in treatment of intraocular pressure in Glaucoma
Author &
Subjects (n)
Drugs
Study Type
Primary
Results
Adverse events/AEs
Date
completed/randomized
Admin. Methods
Duration
Outcome
(summary)
Indication
Subject characteristics
Measure
Crawford &
HT group: 8
NIDA marijuana,
Crossover
No primary -Marijuana decreased IOP by
-Placebo marijuana increased
Merritt (1979) 4 males
smoked
outcome
37-44% from baseline.
heart rate for 10 minutes in
4 females
0%, 2.8% THC
4, 1-day
measure is
-The maximal decrease in
both groups.
Hypertensive
sessions, no specified
IOP was significantly greater
-The maximal increase in heart
and
NT group: 8
Smoking
time
in HT (-14mmHg) than NT (- rate was significantly greater in
Normotensive 4 males
Procedure:
between
Related
9mmHg) after marijuana .
NT than HT after marijuana.
Glaucoma
4 females
-instructed to
sessions
outcome
-The maximal decrease in
inhale 20 times
measure
blood pressure was
Inclusion Criteria:
deeply and retain
was IOP
significantly greater in HT than
-documented glaucoma
smoke in lungs
NT after marijuana.
-smoke
Previous Marijuana
marijuana/placebo
Experience:
cigarette in 5
-all were marijuana naïve minutes

Merritt et al.
(1980)
Glaucoma

Exclusion Criteria:
-coronary artery disease
18
12 males
6 females
(31 glaucoma eyes,
analyzed results for each
eye)
Inclusion Criteria:
-documented glaucoma
Previous Marijuana
Experience:
-9 subjects had used
marijuana at least once

QD
NIDA marijuana,
smoked
0%, 2% THC
Smoking
Procedure:
-None described
-smoked 1
marijuana/placebo
cigarette over 1020 minutes

Crossover
2, 1-day
sessions

No primary
outcome
measure is
specified
Related
outcome
measure
was IOP

-Marijuana significantly
decreased IOP compared to
placebo

-Marijuana significantly
increased heart rate compared
to placebo
-Blood pressure significantly
decreased after marijuana
-All subjects experienced
hunger, thirst, euphoria,
drowsy, and feeling cold
-Observed adverse events were
greater in marijuana naïve
subjects than in subjects with
prior marijuana experience.

QD
AEs:
-5 subjects postural
hypotension
-8 subjects anxiety with

Exclusion Criteria:
-cardiac, neurological,

112

 Author &
Date
Indication

Subjects (n)
completed/randomized
Subject characteristics
and psychiatric
dysfunction

Drugs
Admin. Methods

Study Type
Duration

Primary
Outcome
Measure

Results
(summary)

Adverse events/AEs

tachycardia and palpitations

AE=Adverse Event; HT=Hypertensive; IOP=Intraocular pressure; NIDA=National Institute of Drug Abuse; NT=Normotensive; QD=drug administered one time
per day; THC=delta-9-tetrahydrocannbinol

113

 Table 5: Randomized, controlled, double-blind trails examining smoked marijuana in treatment of asthma
Author &
Subjects (n)
Drugs
Study
Primary
Results
Date
completed/randomized
Admin. Methods
Design
Outcome
(summary)
Indication Subject characteristics
Duration
Measure
Tashkin et
10
NIMH (NIDA)
Crossover
No primary -Marijuana significantly
al. (1974)
5 males
marijuana, smoked
outcome
increased sGaw (33-48%)
5 females
0%, 2% THC
4, 1-day
measure is
compared to placebo and
Bronchial
sessions,
specified
baseline
Asthma
Inclusion Criteria:
Dronabinol, oral
with at
-diagnosis of bronchial
0, 15mg
least 48
Related
asthma
hours
outcome
-asthma relieved by
Dosing is 7mg/kg of between
measure
bronchodilator
body weight of
sessions
was sGaw
medication
plant material
-clinically stable
Smoking Procedure:
Previous Marijuana
smoking of
Experience:
marijuana cigarette
-7 subjects had previous with each puff
exposure to marijuana
consisting of:
-amount of exposure <1 1) 2-4s deep inhale
cigarette/month
smoke,
2) 15s hold smoke
Exclusion Criteria:
in lungs
-no marijuana use ≤7
3) 5s exhale and
days of study
breath normally
-psychiatric illness
4) repeat till entire
cigarette is smoked

Adverse events/AEs

-Marijuana initially significantly
increased pulse rate compared
to placebo, and then at 90
minutes pulse rate was
significantly decreased
compared to baseline.
-All subjects felt intoxicated
after marijuana.

QD
AE=Adverse Event; NIDA=National Institute of Drug Abuse; QD=drug administered one time per day; sGaw=Specific Airway Conductance; THC=delta-9tetrahydrocannbinol

114

 U.S. Department of Justice - Drug Enforcement Administration
Schedule of Controlled Substances: Maintaining Marijuana in Schedule I of the
Controlled Substances Act
Background, Data, and Analysis: Eight Factors Determinative of Control and
Findings Pursuant to 21 U.S.C. 812(b)
Prepared by: Office of Diversion Control, Drug and Chemical Evaluation Section,
Washington, D.C. 20537
July 2016
BACKGROUND
On November 30, 2011, Governors Lincoln D. Chafee of Rhode Island and Christine O.
Gregoire of Washington submitted a petition to the Drug Enforcement Administration
(DEA) to initiate proceedings for a repeal of the rules or regulations that place
marijuana38 in schedule I of the Controlled Substances Act (CSA). The petition requests
that marijuana39 and “related items” be rescheduled in schedule II of the CSA. The
petitioners claim that:
1. Cannabis has accepted medical use in the United States;
2. Cannabis is safe for use under medical supervision;
3. Cannabis for medical purposes has a relatively low potential for
abuse, especially in comparison with other schedule II drugs.
The DEA accepted this petition for filing on January 30, 2012.
The Attorney General may by rule transfer a drug or other substance between schedules
of the CSA if she finds that such drug or other substance has a potential for abuse, and
makes the findings prescribed by 21 U.S.C. 812(b) for the schedule in which such drug is
to be placed. 21 U.S.C. 811(a)(1). The Attorney General has delegated this
responsibility to the Acting Administrator of the DEA. 28 C.F.R. § 0.100(b).
In accordance with 21 U.S.C. 811(b), after gathering the necessary data, the DEA
submitted the petition and necessary data to the Department of Health and Human
Services (HHS) on June 11, 2013, and requested that HHS provide a scientific and
medical evaluation and scheduling recommendation for marijuana. In documents dated

38

The Controlled Substances Act (CSA) defines marijuana as: “All parts of the plant Cannabis sativa L.,
whether growing or not; the seeds thereof; the resin extracted from any part of such plant; and every
compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds or resin. Such
term does not include the mature stalks of such plant, fiber produced from such stalks, oil or cake made
from the seeds of such plant, any other compound, manufacture, salt, derivative, mixture, or preparation of
such mature stalks (except the resin extracted there from), fiber, oil, or cake, or the sterilized seed of such
plant which is incapable of germination.” 21 U.S.C. 802(16). Note that “marihuana” is the spelling used in
the CSA. This document uses the spelling that is more common in current usage, “marijuana.”
39
Petitioners defined marijuana as all cultivated strains of cannabis.

1

 June 3 and June 25, 2015, the acting Assistant Secretary for Health of the HHS40
recommended to the DEA that marijuana continue to be controlled in Schedule I of the
CSA, and provided to the DEA its scientific and medical evaluation titled “Basis for the
Recommendation for Maintaining Marijuana in Schedule I of the Controlled Substances
Act.” The HHS’s recommendations are binding on the DEA as to scientific and medical
matters. 21 U.S.C. 811(b).
Before initiating proceedings to reschedule a substance, the CSA requires the Acting
Administrator to determine whether the HHS scheduling recommendation, scientific and
medical evaluation, and “all other relevant data” constitute substantial evidence that the
drug should be rescheduled as proposed. 21 U.S.C. 811(b). The Acting Administrator
must determine whether there is substantial evidence to conclude that the drug meets the
criteria for placement in another schedule based on the criteria set forth in 21 U.S.C.
812(b). The CSA requires that both the DEA and the HHS consider the eight factors
specified by Congress in 21 U.S.C. 811(c). This document lays out those considerations
and is organized according to the eight factors. As DEA sets forth in detail below, the
evidence shows:
1. Actual or relative potential for abuse. Marijuana has a high potential for
abuse. Preclinical and clinical data show that it has reinforcing effects
characteristic of drugs of abuse. National databases on actual abuse show
marijuana is the most widely abused drug, including significant numbers of
substance abuse treatment admissions. Data on marijuana seizures show
widespread availability and trafficking.
2. Scientific evidence of its pharmacological effect. The scientific understanding
of marijuana, cannabinoid receptors, and the endocannabinoid system
continues to be studied and elucidated. Marijuana produces various
pharmacological effects, including subjective (e.g., euphoria, dizziness,
disinhibition), cardiovascular, acute and chronic respiratory, immune system,
and prenatal exposure effects, as well as behavioral and cognitive impairment.
3. Current scientific knowledge. There is no currently accepted medical use for
marijuana in the United States. Marijuana sources are derived from numerous
cultivated strains and may have different levels of Δ9-THC and other
cannabinoids. Under the five-element test for currently accepted medical use
discussed in more detail below and upheld by the Court of Appeals for the
District of Columbia in Alliance for Cannabis Therapeutics v. DEA, 15 F.3d
1131, 1135 (D.C. Cir. 1994) (hereinafter “ACT”), there is no complete
scientific analysis of marijuana’s chemical components; there are not adequate
40

As set forth in a memorandum of understanding entered into by the HHS, the Food and Drug
Administration (FDA), and the National Institute on Drug Abuse (NIDA), the FDA acts as the lead agency
within the HHS in carrying out the Secretary’s scheduling responsibilities under the CSA, with the
concurrence of the NIDA. 50 FR 9518, Mar. 8, 1985. The Secretary of the HHS has delegated to the
Assistant Secretary for Health of the HHS the authority to make domestic drug scheduling
recommendations.

116

 safety studies; there are not adequate and well-controlled efficacy studies;
there is not a consensus of medical opinion concerning medical applications
of marijuana; and the scientific evidence regarding marijuana’s safety and
efficacy is not widely available. To date, scientific and medical research has
not progressed to the point that marijuana has a currently accepted medical
use, even under conditions where its use is severely restricted.
4. History and current pattern of abuse. Marijuana continues to be the most
widely used illicit drug. In 2014, there were 22.2 million current users. There
were also 2.6 million new users, most of whom were less than 18 years of age.
During the same period, marijuana was the most frequently identified drug
exhibit in federal, state, and local forensic laboratories.
5. Scope, duration, and significance of abuse. Abuse of marijuana is widespread
and significant. In 2014, for example, an estimated 6.5 million people aged
12 or older used marijuana on a daily or almost daily basis over a 12-month
period. In addition, a significant proportion of all admissions for substance
abuse treatment are for marijuana/hashish as their primary drug of abuse. In
2013, 16.8% of all such admissions--281,991 over the course of the year-were for primary marijuana/hashish abuse.
6. Risk, if any, to public health. Together with the health risks outlined in terms
of pharmacological effects above, public health risks from acute use of
marijuana include impaired psychomotor performance, impaired driving, and
impaired performance on tests of learning and associative processes. Chronic
use of marijuana poses a number of other risks to the public health including
physical as well as psychological dependence.
7. Psychic or physiological dependence liability. Long-term, heavy use of
marijuana can lead to physical dependence and withdrawal following
discontinuation, as well as psychic or psychological dependence. In addition,
a significant proportion of all admissions for treatment for substance abuse are
for primary marijuana abuse; in 2013, 16.8% of all admissions were for
primary marijuana/hashish abuse, representing 281,991 individuals.
8. Immediate precursor. Marijuana is not an immediate precursor of any
controlled substance.
As specified in 21 U.S.C. 812(b)(1), in order for a substance to be placed in schedule I,
the Acting Administrator must find that:
A. The drug or other substance has a high potential for abuse.
B. The drug or other substance has no currently accepted medical use
in treatment in the United States.
C. There is a lack of accepted safety for use of the drug or other
substance under medical supervision.
117

 To be classified in another schedule under the CSA (e.g., II, III, IV, or V), a substance
must have a “currently accepted medical use in treatment in the United States.” 21
U.S.C. 812(b)(2)–(5). A substance also may be placed in schedule II if it is found to have
“a currently accepted medical use with severe restrictions.” 21 U.S.C. 812(b)(2). If a
controlled substance has no such currently accepted medical use, it must be placed in
schedule I. See Notice of Denial of Petition, 66 FR 20038 (Apr. 18, 2001) (“Congress
established only one schedule—schedule I—for drugs of abuse with ‘no currently
accepted medical use in treatment in the United States’ and ‘lack of accepted safety for
use . . . under medical supervision.’”).
A drug that is the subject of an approved new drug application (NDA) or abbreviated new
drug application (ANDA) under Federal Food, Drug, and Cosmetic Act (21 U.S.C. 355),
is considered to have a currently accepted medical use in treatment in the United States
for purposes of the CSA . The HHS stated in its review, however, that FDA has not
approved any NDA for marijuana for any indication.
In the absence of NDA or ANDA approval, DEA has established a five-element test for
determining whether the drug has a currently accepted medical use in treatment in the
United States. Under this test, a drug will be considered to have a currently accepted
medical use only if the following five elements are satisfied:
1.
2.
3.
4.
5.

The drug's chemistry is known and reproducible;
There are adequate safety studies;
There are adequate and well-controlled studies proving efficacy;
The drug is accepted by qualified experts; and
The scientific evidence is widely available.

(57 FR 10499, 10506 (March 26, 1992)). See also ACT, 15 F.3d at 1135.
As discussed in Factor 3, below, HHS concluded, and DEA agrees, that the scientific
evidence is insufficient to demonstrate that marijuana has a currently accepted medical
use under the five-element test. The evidence was insufficient in this regard also when
the DEA considered petitions to reschedule marijuana in 1992 (57 FR 10499),41 in 2001
(66 FR 20038), and in 2011 (76 FR 40552)42. Little has changed since 2011 with respect
to the lack of clinical evidence necessary to establish that marijuana has a currently
accepted medical use. No studies have scientifically assessed the efficacy and full safety
profile of marijuana for any specific medical condition.
The limited existing clinical evidence is not adequate to warrant rescheduling of
marijuana under the CSA. To the contrary, the data in this scheduling review document
show that marijuana continues to meet the criteria for schedule I control under the CSA
for the following reasons:
41
42

See Alliance for Cannabis Therapeutics v. DEA, 15 F.3d 1131 (D.C. Cir. 1994).
See Americans for Safe Access v. DEA, 706 F.3d 438 (D.C. Cir. 2013)(rhg den. 2013).

118

 1. Marijuana has a high potential for abuse.
2. Marijuana has no currently accepted medical use in treatment in the
United States.
3. Marijuana lacks accepted safety for use under medical supervision.
FACTOR 1: THE DRUG’S ACTUAL OR RELATIVE POTENTIAL FOR ABUSE
Marijuana is the most commonly abused illegal drug in the United States. It is also the
most commonly used illicit drug by high school students in the United States. Further,
marijuana is the most frequently identified drug by state, local and federal forensic
laboratories. Marijuana’s main psychoactive ingredient, Δ9-tetrahydrocannabinol (Δ9THC),43 is an effective reinforcer in laboratory animals, including primates and rodents.
These animal studies both predict and support the observations that marijuana produces
reinforcing effects in humans. Such reinforcing effects can account for the repeated
abuse of marijuana.
A. Indicators of Abuse Potential
The HHS has concluded in its document, “Basis for the Recommendation for
Maintaining Marijuana in Schedule I of the Controlled Substances Act,” that marijuana
has a high potential for abuse. The finding of “abuse potential” is critical for control
under the Controlled Substances Act (CSA). Although the term is not defined in the
CSA, guidance in determining abuse potential is provided in the legislative history of the
Act (Comprehensive Drug Abuse Prevention and Control Act of 1970, H.R. Rep. No. 911444, 91st Cong., Sess. 2 (1970), reprinted in 1970 U.S.C.C.A.N. 4566, 4603).
Accordingly, the following items are indicators that a drug or other substance has
potential for abuse:
 There is evidence that individuals are taking the drug or drugs containing
such a substance in amounts sufficient to create a hazard to their health or to
the safety of other individuals or of the community; or
 There is significant diversion of the drug or drugs containing such a
substance from legitimate drug channels; or
 Individuals are taking the drug or drugs containing such a substance on their
own initiative rather than on the basis of medical advice from a practitioner
licensed by law to administer such drugs in the course of his professional
practice; or
 The drug or drugs containing such a substance are new drugs so related in
their action to a drug or drugs already listed as having a potential for abuse
to make it likely that the drug will have the same potentiality for abuse as such
43

The terms Δ9-THC and THC are used interchangeably though out this document.

119

 drugs, thus making it reasonable to assume that there may be significant
diversions from legitimate channels, significant use contrary to or without
medical advice, or that it has a substantial capability of creating hazards to
the health of the user or to the safety of the community.
Of course, evidence of actual abuse of a substance is indicative that a drug has a potential
for abuse.
In its recommendation, the HHS analyzed and evaluated data on marijuana as applied to
each of the above four criteria. The analysis presented in the recommendation (HHS,
2015) is discussed below:
1. There is evidence that individuals are taking the drug or drugs containing
such a substance in amounts sufficient to create a hazard to their health or to
the safety of other individuals or of the community.
The HHS stated that some individuals are taking marijuana in amounts
sufficient to create a hazard to their health and to the safety of other
individuals and the community. Data from national databases on actual abuse
of marijuana support the idea that a large number of individuals use
marijuana. In its recommendation (HHS, 2015), the HHS presented data from
the National Survey on Drug and Health (NSDUH) of the Substance Abuse
and Mental Health Services Administration (SAMHSA) and the Monitoring
the Future (MTF) survey of the National Institute on Drug Abuse (NIDA), and
the DEA has since updated this information. The most recent data from
SAMHSA’s NSDUH in 2014 reported that marijuana was the most used illicit
drug. Among Americans aged 12 years and older, an estimated 22.2 million
Americans used marijuana within the past month according to the 2014
NSDUH. In 2004, an estimated 14.6 million individuals reported using
marijuana within the month prior to the study. The estimated rates in 2014
thus reflect an increase of approximately 7.6 million individuals over a 10year period. According to the 2013 NSDUH report, an estimated 19.8 million
individuals reported using marijuana. Thus, over a period of one year (2013
NSDUH – 2014 NSDUH), there was an estimated increase of 2.4 million
individuals in the United States using marijuana.
The results from the 2015 Monitoring the Future survey of 8th, 10th, and 12th
grade students indicate that marijuana was the most widely used illicit drug in
these age groups. Current monthly use was 6.5% of 8th graders, 14.8% of 10th
graders, and 21.3% of 12th graders. The Treatment Episode Data Set (TEDS)
in 2013 reported that marijuana abuse was the primary factor in 16.8 percent
of non-private substance-abuse treatment facility admissions. In 2011,
SAMHSA’s Drug Abuse Warning Network (DAWN) reported that marijuana
was mentioned in 36.4% (455,668 out of approximately 1.25 million) of illicit
drug-related Emergency Department (ED) visits.
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 Data on the extent and scope of marijuana abuse are presented under Factors 4
and 5 of this analysis. Discussion of the health effects of marijuana is
presented under Factor 2, and the assessment of risk to the public health posed
by acute and chronic marijuana abuse is presented under Factor 6 of this
analysis.
2. There is significant diversion of the drug or drugs containing such a
substance from legitimate drug channels.
In accordance with the CSA, the only lawful source of marijuana in the United
States is that produced and distributed for research purposes under the
oversight of NIDA and in conformity with United States obligations under the
Single Convention on Narcotic Drugs.44 The HHS stated that there is a lack
of significant diversion from legitimate drug sources, but that this is likely due
to high availability of marijuana from illicit sources. Marijuana is not an
FDA-approved drug product. Neither a New Drug Application (NDA) nor a
Biologics License Application (BLA) has been approved for marketing in the
United States. However, the marijuana used for nonclinical and clinical
research represents a very small amount of the total amount of marijuana
available in the United States and therefore information about marijuana
diversion from legitimate sources is limited or not available.
The DEA notes that the magnitude of the demand for illicit marijuana is
evidenced by information from a number of databases presented under Factor
4. Briefly, marijuana is the most commonly used illegal drug in the United
States. It is also the most commonly used illicit drug by American high
schoolers. Marijuana is the most frequently identified drug in state, local, and
federal forensic laboratories, with increasing amounts of both domestically
grown and of illicitly smuggled marijuana.
Given that marijuana has long been the most widely trafficked and abused
controlled substance in the United States, and that all aspects of such illicit
activity are entirely outside of the closed system of distribution mandated by
the CSA, it may well be the case that there is little thought given to diverting
marijuana from the small supplies produced for legitimate research purposes.
Thus, the lack of data indicating diversion of marijuana from legitimate
channels to the illicit market is not indicative of a lack of potential for abuse
of the drug.

44

See 76 FR 51403, 51409-51410 (2011) (discussing cannabis controls required under the Single
Convention).

121

 3. Individuals are taking the drug or drugs containing such a substance on their
own initiative rather than on the basis of medical advice from a practitioner
licensed by law to administer such drugs in the course of his professional
practice.
The HHS stated that the FDA has not evaluated or approved an NDA or BLA
for marijuana for any therapeutic indication. Consistent with federal law,
therefore, an individual legitimately can take marijuana based on medical
advice from a practitioner only by participating in research that is being
conducted under an Investigational New Drug (IND) application. The HHS
noted that there are several states as well as the District of Columbia which
have passed laws allowing for individuals to use marijuana for purported
"medical" use under certain circumstances, but data are not available yet to
determine the number of individuals using marijuana under these state laws.
Nonetheless, according to 2014 NSDUH data, 22.2 million American adults
currently use marijuana (SAMHSA, 2015a). Based on the large number of
individuals who use marijuana and the lack of an FDA-approved drug
product, the HHS concluded that the majority of individuals using marijuana
do so on their own initiative rather than by following medical advice from a
licensed practitioner.
4. The drug or drugs containing such a substance are new drugs so related in
their action to a drug or drugs already listed as having a potential for abuse
to make it likely that the drug will have the same potentiality for abuse as such
drugs, thus making it reasonable to assume that there may be significant
diversions from legitimate channels, significant use contrary to or without
medical advice, or that it has a substantial capability of creating hazards to
the health of the user or to the safety of the community.
Marijuana and its primary psychoactive ingredient, Δ9-THC, are controlled
substances in schedule I under the CSA.
The HHS stated that one approved, marketed drug product contains synthetic
Δ9-THC, also known as dronabinol, and another approved, marketed drug
product contains a cannabinoid-like synthetic compound that is structurally
related to Δ9-THC, the main active component in marijuana. Both products
are controlled under the CSA.
Marinol is a schedule III drug product containing synthetic Δ9-THC
(dronabinol) formulated in sesame oil in soft gelatin capsules. Marinol was
approved by the FDA in 1985 for the treatment of nausea and vomiting
associated with cancer chemotherapy in patients who did not respond to
conventional anti-emetic treatments. In 1992, FDA approved Marinol for the
treatment of anorexia associated with weight loss in patients with acquired
immunodeficiency syndrome (AIDS). Marinol was originally placed into
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 schedule II and later rescheduled to schedule III under the CSA due to the low
reports of abuse relative to marijuana.
Cesamet is a drug product containing the schedule II substance nabilone, a
synthetic substance structurally related to Δ9-THC. Cesamet was approved for
marketing by the FDA in 1985 for the treatment of nausea and vomiting
associated with cancer chemotherapy. All other naturally occurring
cannabinoids in marijuana and their synthetic equivalents with similar
chemical structure and pharmacological activity are already included as
schedule I drugs under the CSA.
B. Abuse Liability Studies
In addition to the indicators suggested by the CSA’s legislative history, data as to
preclinical and clinical abuse liability studies, as well as actual abuse, including
clandestine manufacture, trafficking, and diversion from legitimate sources, are
considered in this factor.
Abuse liability evaluations are obtained from studies in the scientific and medical
literature. There are many preclinical measures of a drug’s effects that when taken
together provide an accurate prediction of the human abuse liability. Clinical studies of
the subjective and reinforcing effects in humans and epidemiological studies provide
quantitative data on abuse liability in humans and some indication of actual abuse trends.
Both preclinical and clinical studies have clearly demonstrated that marijuana and Δ9THC possess the attributes associated with drugs of abuse: they function as a positive
reinforcer to maintain drug-seeking behavior, they function as a discriminative stimulus,
and they have dependence potential.
Preclinical and most clinical abuse liability studies have been conducted with the
psychoactive constituents of marijuana, primarily Δ9-THC and its metabolite, 11hydroxy-Δ9-THC. Δ9-THC’s subjective effects are considered to be the basis for
marijuana’s abuse liability. The following studies provide a summary of that data.
1. Preclinical Studies
Δ9-THC, the primary psychoactive component in marijuana, is an effective
reinforcer in laboratory animals, including primates and rodents, as these animals
will self-administer Δ9-THC. These animal studies both predict and support the
observations that Δ9-THC, whether smoked as marijuana or administered by other
routes, produces reinforcing effects in humans. Such reinforcing effects can
account for the repeated abuse of marijuana.
a. Drug Discrimination Studies
The drug discrimination paradigm is used as an animal model of human
subjective effects (Solinas et al., 2006) and is a method where animals are
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 able to indicate whether a test drug is able to produce physical or
psychological changes similar to a known drug of abuse. Animals are trained
to press one bar (in an operant chamber) when they receive a known drug of
abuse and another bar when they receive a placebo. When a trained animal
receives a test drug, if the drug is similar to the known drug of abuse, it will
press the bar associated with the drug.
Discriminative stimulus effects of Δ9-THC have specificity for the
pharmacological effects of cannabinoids found in marijuana (Balster and
Prescott, 1992; Browne and Weissman, 1981; Wiley et al., 1993; Wiley et al.,
1995). As mentioned by the HHS, the discriminative stimulus effects of
cannabinoids appear to be unique because abused drugs of other classes
including stimulants, hallucinogens, opioids, benzodiazepines, barbiturates,
NMDA antagonists, and antipsychotics do not fully substitute for Δ9-THC.
Laboratory animals including monkeys (McMahon et al., 2009), mice
(McMahon et al., 2008), and rats (Gold et al., 1992) are able to discriminate
cannabinoids from other drugs and placebo. The major active metabolite of
Δ9-THC, 11-hydroxy-Δ9-THC, generalizes to Δ9-THC (Browne and
Weissman, 1981). In addition, according to the HHS, twenty-two other
cannabinoids found in marijuana also substitute for Δ9-THC. At least one
cannabinoid, CBD, does not substitute for Δ9-THC in rats (Vann et al., 2008).
b. Self-Administration Studies
Animal self-administration behavior associated with a drug is a commonly
used method for evaluating if the drug produces rewarding effects and for
predicting abuse potential (Balster, 1991; Balster and Bigelow, 2003). Drugs
that are self-administered by animals are likely to produce rewarding effects
in humans. As mentioned in the HHS review document, earlier attempts to
demonstrate self-administration of Δ9-THC were unsuccessful and
confounded by diet restrictions, animal restraint, and known analgesic activity
of Δ9-THC at testing doses (Tanda and Goldberg, 2003; Justinova et al.,
2003). Self-administration of Δ9-THC was first demonstrated by Tanda et al.
(2000). Tanda et al. (2000) showed that squirrel monkeys that were initially
trained to self-administer cocaine (30 µg/kg, i.v.) self-administered 2 µg/kg
Δ9-THC (i.v.) and at a rate of 30 injections per one hour session. Tanda et al.
(2000) used a lower dose of Δ9-THC that was rapidly delivered (0.2 ml
injection over 200 ms) than in previous self-administration studies such that
analgesic activity of Δ9-THC was not a confounding factor. The authors also
stated that the doses were comparable to those doses used by humans who
smoke marijuana. A CB1 receptor antagonist (SR141716) blocked this
rewarding effect of THC.
Justinova et al. (2003) were able to demonstrate self-administration of Δ9THC in drug-naïve squirrel monkeys (no previous exposure to other drugs).
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 The authors tested the monkeys with several doses of Δ9-THC (1, 2, 4, 8, and
16 µg/kg, i.v.) and found that the maximal rates of self-administration were
observed with the 4 µg/kg/infusion. Subsequently, Braida et al. (2004)
reported that rats will self-administer Δ9-THC when delivered
intracerebroventricularly (i.c.v.), but only at the lowest doses tested (0.01 –
0.02 µg/infusion, i.c.v.).
Self-administration behavior with Δ9-THC was found to be antagonized in rats
and squirrel monkeys by rimonabant (SR141716A, CB1 antagonist) and the
opioid antagonists (naloxone and naltrexone) (Tanda et al., 2000; Braida et al.,
2004; Justinova et al., 2004).
c. Conditioned Place Preference Studies
Conditioned place preference (CPP) is a behavioral assay where animals are
given the opportunity to spend time in two distinct environments: one where
they previously received a drug and one where they received a placebo. If the
drug is reinforcing, animals in a drug-free state will choose to spend more
time in the environment paired with the drug when both environments are
presented simultaneously.
CPP has been demonstrated with Δ9-THC in rats but only at low doses (0.075
– 1.0 mg/kg, i.p.; Braida et al., 2004). Rimonabant (0.25 – 1.0 mg/kg, i.p.)
and naloxone (0.5 – 2.0 mg/kg, i.p.) antagonized Δ9-THC-mediated CPP
(Braida et al., 2004). However, in another study with rats, rimonabant was
demonstrated to induce CPP at doses ranging from 0.25 – 3.0 mg/kg (Cheer et
al., 2000). Mice without µ-opioid receptors did not exhibit CPP to Δ9-THC
(paired with 1 mg/kg Δ9-THC, i.p.) (Ghozland et al., 2002).
2. Clinical Studies
In its scientific review (HHS, 2015), the HHS provided a list of common
subjective psychoactive responses to cannabinoids based on information from
several references (Adams and Martin, 1996; Gonzalez, 2007; Hollister, 1986;
Hollister, 1988; Institute of Medicine, 1982). Furthermore, Maldonado (2002)
characterized these subjective responses as pleasurable to most humans and are
generally associated with drug-seeking and/or drug-taking. Later studies
(Scherrer et al., 2009; Zeiger et al., 2010) reported that high levels of positive
psychoactive effects correlate with increased marijuana use, abuse, and
dependence. The list of the common subjective psychoactive effects provided by
the HHS (HHS, 2015) is presented below:
1) Disinhibition, relaxation, increased sociability, and
talkativeness.
2) Increased merriment and appetite, and even exhilaration at high
doses.
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 3) Enhanced sensory perception, which can generate an increased
appreciation of music, art, and touch.
4) Heightened imagination, which can lead to a subjective sense of
increased creativity.
5) Initial dizziness, nausea, tachycardia, facial flushing, dry mouth,
and tremor.
6) Disorganized thinking, inability to converse logically, time
distortions, and short-term memory impairment.
7) Ataxia and impaired judgment, which can impede driving ability
or lead to an increase in risk-taking behavior.
8) Illusions, delusions, and hallucinations that intensify with higher
doses.
9) Emotional lability, incongruity of affect, dysphoria, agitation,
paranoia, confusion, drowsiness, and panic attacks, which are
more common in inexperienced or high-dosed users.
The HHS mentioned that marijuana users prefer higher concentrations of the
principal psychoactive component (Δ9-THC) over lower concentrations. In a
clinical study with marijuana users (n = 12, usage ranged from once a month to 4
times a week), subjects were given a choice of 1.95% Δ9-THC marijuana or
0.63% Δ9-THC marijuana after sampling both marijuana cigarettes in two choice
sessions. The marijuana cigarette with high THC was chosen in 21 out of 24
choice sessions or 87.5% of the time (Chait and Burke, 1994). Furthermore, in a
double-blind study, frequent marijuana users (n = 11, usage at least 2 times per
month with at least 100 occasions) when given a low-dose of oral Δ9-THC (7.5
mg) were able to distinguish the psychoactive effects better than occasional users
(n = 10, no use within the past 4 years with 10 or fewer lifetime uses) and also
experienced fewer sedative effects (Kirk and de Wit, 1999).
Marijuana has also been recognized by scientific experts to have withdrawal
symptoms (negative reinforcement) following moderate and heavy use. As
discussed further in Factor 7, the DEA notes that the American Psychiatric
Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders, Fifth
Edition (DSM-5) included a list of withdrawal symptoms following marijuana
[cannabis] use (DSM-5, 2013).
C. Actual Abuse of Marijuana - National Databases Related to Marijuana Abuse
and Trafficking
Marijuana continues to be the most widely used illicit drug. Evidence of actual abuse can
be defined by episodes/mentions in databases indicative of abuse/dependence. The HHS
provided in its recommendation (HHS, 2015) information relevant to actual abuse of
marijuana including data results from the National Survey on Drug Use and Health
(NSDUH), a Monitoring the Future (MTF) survey, the Drug Abuse Warning Network
(DAWN), and the Treatment Episode Data Set (TEDS). These data sources provide
quantitative information on many factors related to abuse of a particular substance,
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 including incidence and patterns of use, and profile of the abuser of specific substances.
The DEA is providing updated information from these databases in this discussion. The
DEA also includes data on trafficking and illicit availability of marijuana from DEA
databases including the National Forensic Laboratory Information System (NFLIS) and
the National Seizure System (NSS), formerly the Federal-wide Drug Seizure System
(FDSS), as well as other sources of data specific to marijuana, including the Potency
Monitoring Project and the Domestic Cannabis Eradication and Suppression Program
(DCE/SP).
1. National Survey on Drug Use and Health (NSDUH)
The National Survey on Drug Use and Health (NSDUH) is conducted annually by
the Department of Health and Human Service’s Substance Abuse and Mental
Health Services Administration (SAMHSA). SAMHSA is the primary source of
estimates of the prevalence and incidence of pharmaceutical drugs, illicit drugs,
alcohol, and tobacco use in the United States. The survey is based on a nationally
representative sample of the civilian, non-institutionalized population 12 years of
age and older. The survey excludes homeless people who do not use shelters,
active military personnel, and residents of institutional group quarters such as jails
and hospitals.
According to the 2014 NSDUH report, marijuana was the most commonly used
and abused illicit drug. That data showed that there were 22.2 million people who
were past month users (8.4%) among those aged 12 and older in the United States.
(Note: NSDUH figures on marijuana use include hashish use; the relative
proportion of hashish use to marijuana use is very low). Marijuana had the
highest rate of past-year dependence or abuse in 2014. The NSDUH report
estimates that 3.0 million people aged 12 or older used an illicit drug for the first
time in 2014; a majority (70.3%) of these past year initiates reported that their
first drug used was marijuana. Among those who began using illicit drugs in the
past year, 65.6%, 70.3%, and 67.6% reported marijuana as the first illicit drug
initiated in 2012, 2013, and 2014 respectively. In 2014, the average age of
marijuana initiates among 12- to 49-year-olds was 18.5 years. These usage rates
and demographics are relevant in light of the risks presented.
Marijuana had the highest rate of past year dependence or abuse of any illicit drug
in 2014. The 2014 NSDUH report stated that 4.2 million persons were classified
with substance dependence or abuse of marijuana in the past year (representing
1.6% of the total population aged 12 or older, and 59.0% of those classified with
illicit drug dependence or abuse) based on criteria specified in the Diagnostic and
Statistical Manual of Mental Disorders, 4th edition (DSM-IV).
Among past year marijuana users age 12 or older, 18.5% used marijuana on 300
or more days within the previous 12 months in 2014. This translates into 6.5
million people using marijuana on a daily or almost daily basis over a 12-month
period, significantly more than the estimated 5.7 million daily or almost daily
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 users in just the year before. Among past month marijuana users, 41.6% (9.2
million) used the drug on 20 or more days in the past month, a significant increase
from the 8.1 million who used marijuana 20 days or more in 2013.
2. Monitoring the Future (MTF)
Monitoring the Future (MTF) is an ongoing study which is funded under a series
of investigator-initiated competing research grants from the National Institute on
Drug Abuse (NIDA). MTF tracks drug use trends among American adolescents
in the 8th, 10th, and 12th grades. According to its 2015 survey results, marijuana
was the most commonly used illicit drug, as was the case in previous years.
Approximately 6.5% of 8th graders, 14.8% of 10th graders, and 21.3% of 12th
graders surveyed in 2015 reported marijuana use during the past month prior to
the survey. A number of high school students in 2015 also reported daily use in
the past month, including 1.1%, 3.0%, and 6.0% of 8th, 10th, and 12th graders,
respectively.
3. Drug Abuse Warning Network (DAWN), Emergency Department (ED) Visits
The Drug Abuse Warning Network (DAWN) is a public health surveillance
system that monitors drug-related hospital emergency department (ED) visits to
track the impact of drug use, misuse, and abuse in the United States. For the
purposes of DAWN, the term “drug abuse” applies if the following conditions are
met: (1) the case involved at least one of the following: use of an illegal drug, use
of a legal drug contrary to directions, or inhalation of a non-pharmaceutical
substance; and (2) the substance was used for one of the following reasons:
because of drug dependence, to commit suicide (or attempt to commit suicide),
for recreational purposes, or to achieve other psychic effects. Importantly, many
factors can influence the estimates of ED visits, including trends in overall use of
a substance as well as trends in the reasons for ED usage. For instance, some
drug users may visit EDs for life-threatening issues while others may visit to seek
care for detoxification because they needed certification before entering
treatment. Additionally, DAWN data do not distinguish the drug responsible for
the ED visit from other drugs that may have been used concomitantly. As stated
in a DAWN report, "Since marijuana/hashish is frequently present in combination
with other drugs, the reason for the ED visit may be more relevant to the other
drug(s) involved in the episode."
In 2011, marijuana was involved in 455,668 ED visits out of 2,462,948 total ED
visits involving all abuse or misuse in the United States and out of 1.25 million
visits involving abuse or misuse of illicit drugs (excluding alcohol-related visits),
as estimated by DAWN. This is lower than the number of ED visits involving
cocaine (505,224) and higher than the number of ED visits involving heroin
(258,482) and stimulants (e.g., amphetamine, methamphetamine) (159,840).
Visits involving the other major illicit drugs, such as MDMA, GHB, LSD and
other hallucinogens, PCP, and inhalants, were much less frequent, comparatively.
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 In young patients, marijuana is the illicit drug most frequently involved in ED
visits, according to DAWN estimates, with 240.2 marijuana-related ED visits per
100,000 population ages 12 to 17, 443.8 per 100,000 population ages 18 to 20,
and 446.9 per 100,000 population ages 21 to 24.
4. Treatment Episode Data Set (TEDS) System
The Treatment Episode Data Set (TEDS) system is part of the SAMHSA Drug
and Alcohol Services Information System and is a national census of annual
admissions to state licensed or certified, or administratively tracked, substance
abuse treatment facilities. The TEDS system contains information on patient
demographics and substance abuse problems of admissions to treatment for abuse
of alcohol and/or drugs in facilities that report to state administrative data
systems. For this database, the primary substance of abuse is defined as the main
substance of abuse reported at the time of admission. TEDS also allows for the
recording of two other substances of abuse (secondary and tertiary).
In 2011, the TEDS system included 1,928,792 admissions to substance abuse
treatment; in 2012 there were 1,801,385 admissions; and in 2013 there were
1,683,451 admissions. Marijuana/hashish was the primary substance of abuse for
18.3% (352,397) of admissions in 2011; 17.5% (315,200) in 2012; and 16.8%
(281,991) in 2013. Of the 281,991 admissions for marijuana/hashish treatment in
2013, 24.3% used marijuana/hashish daily. Among those treated for
marijuana/hashish as the primary substance in 2013, 27.4% were ages 12 to 17
years and 29.7% were ages 18 to 24 years. Those admitted for marijuana/hashish
were mostly male (72.6%) and non-Hispanic (82.2%). Non-hispanic whites
(43.2%) represented the largest ethnic group of marijuana admissions.
5. Forensic Laboratory Data
Data on marijuana seizures from federal, state, and local forensic laboratories
have indicated that there is significant trafficking of marijuana. The National
Forensic Laboratory System (NFLIS) is a program sponsored by the Drug
Enforcement Administration’s Office of Diversion Control. NFLIS
systematically collects drug identification results and associated information from
drug exhibits encountered by law enforcement and analyzed in federal, state, and
local forensic laboratories. NFLIS is a comprehensive information system that
includes data from 278 individual forensic laboratories that report more than 91%
of the drug caseload in the U.S. NFLIS captures data for all drugs and chemicals
identified and reported by forensic laboratories. More than 1,700 unique
substances are represented in the NFLIS database.
Data from NFLIS showed that marijuana was the most frequently identified drug
in federal, state, and local laboratories from January 2004 through December
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 2014. Marijuana accounted for between 29.47% and 34.84% of all drug exhibits
analyzed annually during that time frame (Table 1).
Table 1. NFLIS Federal, State and Local Forensic Laboratory Data of Marijuana
Reports (other than hashish)
Year
Reports
Percent of Total Reports
2004
454,582
34.42%
2005
483,134
32.53%
2006
520,060
32.55%
2007
525,668
33.66%
2008
526,420
34.07%
2009
536,888
34.30%
2010
544,418
34.91%
2011
495,937
33.42%
2012
485,591
32.02%
2013

452,839

30.70%

2014

432,989

29.27%

2015*

341,162

26.73%

NFLIS database queried 03-23-2016, by date of submission, all drugs reported
*2015 data are still being reported to NFLIS due to normal lag time.

Since 2004, the total number of reports of marijuana and the amount of marijuana
encountered federally has remained high (see data from Federal-wide Drug
Seizure System and Domestic Cannabis Eradication and Suppression Program
below).

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 6. Federal-wide Drug Seizure System
The Federal-wide Drug Seizure System (FDSS) contains information about drug
seizures made within the jurisdiction of the United States by the Drug
Enforcement Administration, the Federal Bureau of Investigation, United States
Customs and Border Protection, and United States Immigration and Customs
Enforcement. It also records maritime seizures made by the United States Coast
Guard. Drug seizures made by other Federal agencies are included in the FDSS
database when drug evidence custody is transferred to one of the agencies
identified above. FDSS is now incorporated into the National Seizure System
(NSS), which is a repository for information on clandestine laboratory and
contraband (chemicals and precursors, currency, drugs, equipment and weapons).
FDSS reports total federal drug seizures [in kilograms (kg)] of substances such as
cocaine, heroin, MDMA, methamphetamine, and cannabis (marijuana and
hashish). The yearly volume of cannabis seized (Table 2), consistently exceeding
a thousand metric tons per year, shows that cannabis is very widely trafficked in
the United States.
Table 2. Total Federal Seizures of Cannabis (Expressed in Kg)
(Source: NSS, U.S. Seizures, EPIC System Portal, queried 08-05-2015)

Cannabis
Marijuana
Hashish

2010
4,071,328
4,070,850
478

2011
3,622,256
3,621,322
934

2012
2,756,439
2,754,457
1,982

2013
2,622,494
2,618,340
4,154

2014
1,768,277
1,767,741
536

7. Potency Monitoring Project
The University of Mississippi’s Potency Monitoring Project (PMP), through a
contract with the National Institute on Drug Abuse (NIDA), analyzes and
compiles data on the Δ9-THC concentrations of marijuana, hashish and hash oil
samples provided by DEA regional laboratories and by state and local police
agencies. After 2010, PMP has analyzed only marijuana samples provided by
DEA regional laboratories. As indicated in Figure 1, the percentage of Δ9-THC
increased from 1995 to 2010 with an average THC content of 3.75% in 1995 and
9.53% in 2010. In examining marijuana samples only provided by DEA
laboratories, the average Δ9-THC content was 3.96% in 1995 in comparison to
11.16% in 2015.

131

 Figure 1. Average Percentage of Δ9-THC in Samples of Seized Marijuana (1995 –
2015)*
(Source: The University of Mississippi Potency Monitoring Program, Quarterly Report
# 131)
14.00%
12.17%

12.00%
10.36%

11.16%

Average THC% (dry wt.)

10.00%
8.14%

8.00%

7.09%

DEA + State Labs

6.00%
4.00%

9.53%

DEA Labs

3.96%
3.75%

2.00%
0.00%

Year
*PMP discontinued analysis of state samples after 2010.
**Data for 2015 are incomplete. Figure 1 contains percentage of Δ 9-THC data through Dec. 22. Due to lack
of funding, 4,177 samples haven’t yet been analyzed.

8. The Domestic Cannabis Eradication and Suppression Program
The Domestic Cannabis Eradication and Suppression Program (DCE/SP) was
established in 1979 to reduce the supply of domestically cultivated marijuana in
the United States. The program was designed to serve as a partnership between
federal, state, and local agencies. Only California and Hawaii were active
participants in the program at its inception. However, by 1982 the program had
expanded to 25 states and by 1985 all 50 states were participants. Cannabis is
cultivated in remote locations and frequently on public lands and illicitly grown in
all states. Data provided by the DCE/SP (Table 3) show that in the United States
in 2014, there were 3,904,213 plants eradicated in outdoor cannabis cultivation
areas compared to 2,597,798 plants in 2000. Significant quantities of marijuana
were also eradicated from indoor cultivation operations. There were 396,620
indoor plants eradicated in 2014 compared to 217,105 eradicated in 2000.

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 Table 3. Domestic Cannabis Eradication, Outdoor and Indoor Plants Seized, 2000–
2014 (Source: Domestic Cannabis Eradication/Suppression Program)
Outdoor
Indoor
Total

2000
2,597,798
217,105
2,814,903

2001
3,068,632
236,128
3,304,760

2002
3,128,800
213,040
3,341,840

2003
3,427,923
223,183
3,651,106

2004
2,996,144
203,896
3,200,040

Outdoor
Indoor
Total

2005
3,938,151
270,935
4,209,086

2006
4,830,766
400,892
5,231,658

2007
6,599,599
434,728
7,034,327

2008
7,562,322
450,986
8,013,308

2009
9,980,038
414,604
10,394,642

Outdoor
Indoor
Total

2010
9,866,766
462,419
10,329,185

2011
6,226,288
509,231
6,735,519

2012
3,631,582
302,377
3,933,959

2013
4,033,513
361,727
4,395,240

2014
3,904,213
396,620
4,300,833

The recent statistics from these various surveys and databases show that marijuana
continues to be the most commonly used illicit drug, with considerable rates of heavy
abuse and dependence. They also show that marijuana is the most readily available illicit
drug in the United States.
Petitioners’ major comments in relation to Factor 1 and the Government’s
responses
1) In Exhibit B, the petitioners compared the effects of marijuana to currently controlled
schedule II substances and made repeated claims about the comparative effects.
The HHS noted that comparisons between marijuana and schedule II substances are
difficult because of differences in the actions of different pharmacological classes of
schedule II drugs in the CSA. The HHS notes that schedule II substances include
stimulant-like drugs (e.g. cocaine, amphetamine), opioids (e.g. fentanyl, oxycodone),
depressant drugs (e.g., pentobarbital), dissociative anesthetics (e.g. phencyclidine), and
naturally occurring plant components (e.g. coca leaves and poppy straw). The
mechanism of action of Δ9-THC and marijuana, which act primarily through the
cannabinoid receptors (discussed further in Factor 2) are completely different from the
above-mentioned classes of schedule II substances. The HHS concludes that the
differences in the mechanisms of action in the various classes of schedule II substances
make it inappropriate to compare the range of those substances with marijuana.
Furthermore, as noted by the HHS, many substances scheduled under the CSA are
evaluated within the context of drug development using data submitted under a New
133

 Drug Application (NDA). However, the petitioners have not identified a specific
indication for use of marijuana and therefore the HHS notes that an appropriate
comparator based on indication cannot be identified.
2) The petitioners indicated that the actual or relative potential of abuse of marijuana is
low. The petitioners state, “Some researchers claim that cannabis is not particularly
addictive. Experts assert that cannabis’s addictive potential parallels caffeine’s.”
(Exhibit B, page 19, lines 20-21). Furthermore, petitioners stated that, “Cannabis use
indicates a lower likelihood of addiction and abuse potential as compared to other
substances.” (Exhibit B, page 22, lines 12-13).
Under the CSA, for a substance to be placed in schedule II, III, IV, or V, it must have a
currently accepted medical use in treatment in the United States.45 As DEA has
previously stated, Congress established only one schedule, schedule I, for drugs of abuse
with "no currently accepted medical use in treatment in the United States." 76 FR 40552
(2011). Thus, any attempt to compare the relative abuse potential of schedule I substance
to that of a substance in another schedule is inconsequential since a schedule I substance
must remain in schedule I until it has been found to have a currently accepted medical use
in treatment in the United States.
Moreover, the petitioners failed to review the indicators of abuse potential, as discussed
in the legislative history of the CSA. The petitioners did not use data on marijuana usage,
diversion, psychoactive properties, and dependence in their evaluation of marijuana abuse
potential. The HHS and the DEA discuss those indicators above in this factor. HHS’s
evaluation of the full range of data led HHS and DEA to conclude that marijuana has a
high potential for abuse.
The petitioners, based on their review of a survey by Gore and Earleywine (2007),
concluded that marijuana has a low abuse potential. Gore and Earleywine surveyed 746
mental health professionals and asked them to rate the addictiveness (based on a sevenpoint scale) of several drugs (heroin, nicotine, cocaine/crack, oxycodone,
methamphetamine, amphetamine, caffeine, alcohol, and marijuana). The petitioners
stated that the health professionals rated marijuana as least addictive of the drugs
surveyed. The DEA notes that the survey cited by the petitioners is based on subjective
opinions from health professionals.

3) The petitioners mentioned that many of the cannabinoids in marijuana decrease the
psychoactive effects of Δ9-THC, and therefore marijuana lacks sufficient abuse
potential for placement into schedule I. Further, the petitioners mentioned on page 4
in Exhibit B (lines 11-15), “While the DEA considers cannabis a schedule I drug, it
classifies dronabinol (Marinol) as schedule III. Dronabinol is 100 percent THC and
is potentially very psychoactive. Natural cannabis typically would be no more than
15 percent THC by weight. Thus it is inconsistent that cannabis, with 15 percent
45

See Americans for Safe Access, 706 F.3d at 440.

134

 weight THC, remains a [s]chedule I drug, while dronabinol, at 100 percent THC, is
schedule III.”
The HHS addressed this issue by indicating that the modulating effects of the other
cannabinoids in marijuana on Δ9-THC have not been demonstrated in controlled studies.
The HHS and the DEA also note that the determination of the abuse potential of a
substance considers not only psychoactive effects but also chemistry, pharmacology,
pharmacokinetics, usage patterns, and diversion history among other measures.
Marinol (dronabinol in sesame oil) was rescheduled from schedule II to schedule III on
July 2, 1999 (64 FR 35928, DEA 1999). In assessing Marinol, HHS compared Marinol
to marijuana on several aspects of abuse potential and found that major differences
between the two, such as formulation, availability, and usage, contribute to differences in
abuse potential. The psychoactive effects from smoking are generally more rapid and
intense than those that occur through oral administration (HHS, 2015; Wesson and
Washburn, 1990; Hollister and Gillespie, 1973). Therefore, as concluded by both the
HHS and the DEA, the delayed onset of action and longer duration of action from an oral
dose of Marinol may contribute in limiting the abuse potential of Marinol relative to
marijuana, which is most often smoked. The HHS also stated that the extraction and
purification of dronabinol from the encapsulated sesame oil mixture of Marinol is highly
complex and difficult, and that the presence of sesame oil mixture may preclude the
smoking of Marinol-laced cigarettes.
Furthermore, marijuana and Marinol show significant differences in actual abuse and
illicit trafficking. There have been no reports of abuse, diversion, or public health risks
due to Marinol. In contrast, 22.2 million American adults report currently using
marijuana (SAMHSA, 2015a). The DEA database, NFLIS, showed that marijuana was
the most frequently identified drug in state and local forensic laboratories from January
2001 to December 2014 and indicates the high availability of marijuana. The differences
in composition, actual abuse, and diversion contribute to the differences in scheduling
between marijuana and Marinol.
Additionally, the FDA approved a New Drug Application (NDA) for Marinol, indicating
a legitimate medical use for Marinol in the United States and allowing for Marinol to be
rescheduled into schedule II and subsequently into schedule III of the CSA. The HHS
mentioned that marijuana and Marinol differ on a wide variety of factors and these
differences are major reasons for differential scheduling of marijuana and Marinol.
Marijuana, as discussed more fully in Factors 3 and 6, does not have a currently accepted
medical use in the United States, is highly abused, and has a lack of accepted safety.
FACTOR 2: SCIENTIFIC EVIDENCE OF THE DRUG’S PHARMACOLOGICAL
EFFECTS, IF KNOWN
The HHS stated that there are large amounts of scientific data on the neurochemistry,
mechanistic effects, toxicology, and pharmacology of marijuana. A scientific evaluation,
as conducted by the HHS and the DEA, of marijuana’s neurochemistry, human and
135

 animal behavioral pharmacology, central nervous system effects, and other
pharmacological effects (e.g. cardiovascular, immunological effects) is presented below.
Neurochemistry
Marijuana contains numerous constituents such as cannabinoids that have a variety of
pharmacological actions. The petition defined marijuana as including all cannabis
cultivated strains. The HHS stated that different marijuana samples derived from various
cultivated strains may differ in their chemical constituents including Δ9-THC and other
cannabinoids. Therefore marijuana products from different strains will have different
biological and pharmacological effects. The chemical constituents of marijuana are
discussed further in Factor 3.
The primary site of action for cannabinoids such as Δ9-THC is at the cannabinoid
receptor. Two cannabinoid receptors, CB1 and CB2, have been identified and
characterized (Battista et al., 2012; Piomelli, 2005) and are G-protein-coupled receptors.
Activation of these inhibitory G-protein-coupled receptors inhibits adenylate cyclase
activity, which prevents conversion of ATP to cyclic AMP. Cannabinoid receptor
activation also results in inhibition of N- and P/Q-type calcium channels and activates
inwardly rectifying potassium channels (Mackie et al., 1995; Twitchell et al., 1997). The
HHS mentioned that inhibition of N-type calcium channels decreases neurotransmitter
release and this may be the underlying mechanism in the ability of cannabinoids to inhibit
acetylcholine, norepinephrine and glutamate from specific areas of the brain. These
cellular actions may underlie the antinociceptive and psychoactive effects of
cannabinoids. Δ9-THC acts as an agonist at cannabinoid receptors.
CB1 receptors are primarily found in the central nervous system and are located mainly
in the basal ganglia, hippocampus and cerebellum of the brain (Howlett et al., 2004).
CB1 receptors are also located in peripheral tissues such as the immune system (De
Petrocellis and Di Marzo, 2009), but the concentration of CB1 receptors there is
considerably lower than in the central nervous system (Herkenham et al., 1990; 1992).
CB2 receptors are found primarily in the immune system and predominantly in B
lymphocytes and natural killer cells (Bouaboula et al., 1993). CB2 receptors are also
found in the central nervous system, primarily in the cerebellum and hippocampus (Gong
et al., 2006).
Two endogenous ligands to the cannabinoid receptors, anandamide and arachidonyl
glycerol (2-AG), were identified in 1992 (Devane et al., 1992) and 1995 (Mechoulam et
al., 1995), respectively. Anandamide is a low-efficacy agonist (Brievogel and Childers,
2000) and 2-AG is a high efficacy agonist (Gonsiorek et al., 2000) to the cannabinoid
receptors. These endogenous ligands are present in both the central nervous system and
in the periphery (HHS, 2015).
Δ9-THC and cannabidiol (CBD) are two of the major cannabinoids in marijuana. Δ9THC is the major psychoactive cannabinoid (Wachtel et al., 2002). Δ9-THC has similar
affinity for CB1 and CB2 receptors and acts as a weak agonist at CB2 receptors. The
136

 HHS indicated that activation of CB1 receptors mediates psychotropic effects of
cannabinoids. CBD has low affinity for both CB1 and CB2 receptors. CBD has
antagonistic effects at CB1 receptors, and some inverse agonistic properties at CB2
receptors.
Animal Behavioral Effects
Animal abuse potential studies (drug discrimination, self-administration, conditioned
place preference) are discussed more fully in Factor 1. Briefly, it was consistently
demonstrated that Δ9-THC, the primary psychoactive component in marijuana, and other
cannabinoids in marijuana have a distinct drug discriminative profile. In addition,
animals self-administer Δ9-THC, and Δ9-THC in low doses produces conditioned place
preference.
Central Nervous System Effects
Psychoactive Effects
The clinical psychoactive effects of marijuana are discussed more fully in Factor 1.
Briefly, the psychoactive effects from marijuana use are considered pleasurable and
associated with drug-seeking or drug-taking (HHS, 2015; Maldonado, 2002). Further, it
was noted by HHS that marijuana users prefer higher concentrations of the principal
psychoactive component (Δ9-THC) over lower concentrations (HHS, 2015).
Studies have evaluated psychoactive effects of THC in the presence of high CBD, CBC,
or CBN ratios. Even though some studies suggest that CBD may decrease some of Δ9THC’s psychoactive effects, the HHS found that the ratios of CBD to Δ9-THC
administered in the studies were not comparable to the amounts found in marijuana used
by most people (Dalton et al., 1976; Karniol et al., 1974; Zwardi et al., 1982). In fact, the
CBD ratios in these studies are significantly higher than the CBD found in most
marijuana currently found on the streets (Mehmedic et al., 2010). HHS indicated that
most of the marijuana available on the street has a high THC and low CBD content and
therefore any lessening of THC’s psychoactive effects by CBD will not occur for most
marijuana users (HHS, 2015). Dalton et al. (1976) reported that when volunteers smoked
cigarettes with a ratio of 7 CBD to 1 Δ9-THC (0.15 mg/kg CBD and 0.025 mg/kg Δ9THC), there was a significant decrease in ratings of acute subjective effects and achieving
a “high” in comparison to smoking Δ9-THC alone. In oral administration studies, the
subjective effects and anxiety produced by combination of CBD and THC in a ratio of at
least 1:2 CBD to Δ9-THC (15, 30, 60 mg CBD to 30 mg Δ9-THC; Karniol et al., 1974) or
a ratio of 2:1 CBD to Δ9-THC (1 mg/kg CBD to 0.5 mg/kg Δ9-THC; Zuardi et al., 1982)
are less than those produced by Δ9-THC administered alone.
In one study (Ilan et al., 2005), the authors calculated the naturally occurring
concentrations of CBC and CBD in marijuana cigarettes with either 1.8 or 3.6% Δ9-THC
by weight. The authors varied the concentrations of CBC and CBD for each
concentration of Δ9-THC in the marijuana cigarettes. Administrations in healthy
137

 marijuana users (n=23) consisted of either: 1) low CBC (0.1% by weight) and low CBD
(0.2% by weight); 2) high CBC (0.5% by weight) and low CBD; 3) low CBC and high
CBD (1.0% by weight); or 4) high CBC and high CBD and the users were divided into
low Δ9-THC (1.8% by weight) and high Δ9-THC (3.6% by weight) groups. Subjective
psychoactive effects were significantly greater for all groups in comparison to placebo
and there were no significant differences in effects among the treatments (Ilan et al.,
2005).
The HHS also referred to a study with Δ9-THC and cannabinol (CBN) (Karniol et al.,
1975). In this study, oral administration of either 12.5, 25, or 50 mg CBN combined with
25 mg Δ9-THC (ratio of at least 1:2 CBN to Δ9-THC) significantly increased subjective
psychoactive ratings of Δ9-THC compared to Δ9-THC alone (Karniol et al., 1975).
Behavioral Impairment
Several factors may influence marijuana's behavioral effects including the duration
(chronic or short term), frequency (daily, weekly, or occasionally), and amount of use
(heavy or moderate). Researchers have examined how long behavioral impairments
persist following chronic marijuana use. These studies used self-reported histories of
exposure duration, frequency, and amount of marijuana use, and administered several
performance and cognitive tests at different time points following marijuana abstinence.
According to HHS, behavioral impairments may persist for up to 28 days of abstinence in
chronic marijuana users.
Psychoactive effects of marijuana can lead to behavioral impairment including cognitive
decrements and decreased ability to operate motor vehicles (HHS, 2015). Block et al.
(1992) evaluated cognitive measures in 48 healthy male subjects following smoking a
marijuana cigarette that contained 2.57% or 19 mg Δ9-THC by weight or placebo. Each
subject participated in eight sessions (four sessions with marijuana; four sessions with
placebo) and several cognitive and psychomotor tests were administered (e.g. verbal
recall, facial recognition, text learning, reaction time). Marijuana significantly impaired
performances in most of these cognitive and psychomotor tests (Block et al., 1992).
Ramaekers et al. (2006) reported that in 20 recreational users of marijuana, acute
administration of 250 µg/kg and 500 µg/kg Δ9-THC in smoked marijuana resulted in
dose-dependent impairments in cognition, motor impulsivity, motor control (tracking
impairments), and risk taking. In another study (Kurzthaler et al., 1999), when 290 µg/kg
Δ9-THC was administered via a smoked marijuana cigarette in 30 healthy volunteers with
no history of substance abuse there were significant impairments of motor speed and
accuracy. Furthermore, administration of 3.95% Δ9-THC in a smoked marijuana
cigarette increased the latency in a task of simulated braking in a vehicle (Liguori et al.,
1998). The HHS noted that the motor impairments reported in these studies (Kurzthaler
et al., 1999; Liguori et al., 1998) are critical skills needed for operating a vehicle.
As mentioned in the HHS document, some studies examined the persistence of the
behavioral impairments immediately after marijuana administration. Some of
138

 marijuana’s acute effects may still be present for at least 24 hours after the acute
psychoactive effects have subsided. In a brief communication, Heishmann et al. (1990)
reported that there were cognitive impairments (digit recall and arithmetic tasks) in two
out of three experienced marijuana smokers for 24 hours after smoking marijuana
cigarettes containing 2.57% Δ9-THC. However, Fant et al. (1998) evaluated subjective
effects and performance measures for up to 25 hours in 10 healthy males after exposure
to either 1.8% or 3.6% Δ9-THC in marijuana cigarettes. Peak decrements in subjective
and performance measures were noted within 2 hours of marijuana exposure but there
were minimal residual alterations in subjective or performance measures at 23 – 25 hours
after exposure.
Persistence of behavioral impairments following repeated and chronic use of marijuana
has also been investigated and was reviewed in the HHS document (HHS, 2015). In
particular, researchers examined how long behavioral impairments last following chronic
marijuana use. In studies examining persistence of effects in chronic and heavy
marijuana users, there were significant decrements in cognitive and motor function tasks
in all studies of up to 27 days, and in most studies at 28 days (Solowij et al., 2002;
Messinis et al., 2006; Lisdahl and Price, 2012; Pope et al., 2002; Bolla et al., 2002; Bolla
et al., 2005). In studies that followed heavy marijuana users for longer than 28 days and
up to 20 years of marijuana abstinence, cognitive and psychomotor impairments were no
longer detected (Fried et al., 2005; Lyons et al., 2004; Tait et al., 2011). For example,
Fried et al. (2005) reported that after 3 months of abstinence from marijuana, any deficits
in intelligence (IQ), memory, and processing speeds following heavy marijuana use were
no longer observed (Fried et al., 2005). In a meta-analysis that examined non-acute and
long-lasting effects of marijuana, any deficits in neurocognitive performance that were
observed within the first month were no longer apparent after approximately one month
of abstinence (Schreiner and Dunn, 2012). HHS further notes that in moderate marijuana
users deficits in decision-making skills were not observed after 25 days of abstinence and
additionally IQ, immediate memory and delayed memory skills were not significantly
impacted as observed with heavy and chronic marijuana users (Fried et al., 2005; HHS,
2015).
As mentioned in the HHS document (HHS, 2015), the intensity and persistence of
neurological impairment from chronic marijuana use also may be dependent on the age of
first use. In two separate smaller scale studies (less than 100 participants per exposure
group), Fontes et al. (2011) and Gruber et al. (2012) compared neurological function in
early onset (chronic marijuana use prior to age 15 or 16) and late onset (chronic
marijuana use after age 15 or 16) heavy marijuana users and found that there were
significant deficits in executive neurological function in early onset users which were not
observed or were less apparent in late onset users. In a prospective longitudinal birth
cohort study following 1,037 individuals (Meier et al., 2012), a significant decrease in IQ
and neuropsychological performance was observed in adolescent-onset users and
persisted even after abstinence from marijuana for at least one year. However, Meier et
al (2012) reported in there was no significant change in IQ in adult-onset users.

139

 The HHS noted that there is some evidence that the severity of the persistent neurological
impairments may also be due in part to the amount of marijuana usage. In the study
mentioned above, Gruber et al. (2012) found that the early onset users consumed three
times as much marijuana per week and used it twice as often as late onset users. Meier et
al. (2012) reported in their study, mentioned above, that there was a correlation between
IQ deficits in adolescent onset users and the increased amount of marijuana used.

Behavioral Effects of Prenatal Exposure
In studies that examined effects of prenatal marijuana exposure, many of the pregnant
women also used alcohol and tobacco in addition to marijuana. Even though other drugs
were used in conjunction with marijuana, there is evidence of an association between
heavy prenatal marijuana exposure and deficits in some cognitive function. There have
been two prospective longitudinal birth cohort studies following individuals prenatally
exposed to marijuana from birth until adulthood: the Ottawa Prenatal Prospective Study
(OPPS; Fried et al., 1980), and the Maternal Health Practices and Child Development
Project (MHPCD; Day et al., 1985). Both longitudinal studies report that heavy prenatal
marijuana use is associated with decreased performance on tasks assessing memory,
verbal and quantitative reasoning in 4-year-olds (Fried and Watkinson, 1990) and in 6
year olds (Goldschmidt et al., 2008). In subsequent studies with the OPPS cohort,
deficits in sustained attention were reported in children ages 6 and 13 – 16 years (Fried et
al., 1992; Fried, 2002) and deficits in executive neurological function were observed in 9and 12-year-old children (Fried et al., 1998). DEA further notes that with the MHPCD
cohort, follow-up studies reported an increased rate of delinquent behavior (Day et al.,
2011) and decreased achievement test scores (Goldschmidt et al., 2012) at age 14. When
the MHPCD cohort was followed to age 22, there was a marginal (p = 0.06) increase in
psychosis with prenatal marijuana exposure and early onset of marijuana use (Day et al.,
2015).
Association of Marijuana Use with Psychosis
There has been extensive research to determine whether marijuana usage is associated
with development of schizophrenia or other psychoses, and the HHS indicated that the
available data do not suggest a causative link between marijuana and the development of
psychosis (HHS, 2015; Minozzi et al., 2010). As mentioned in the HHS review (HHS,
2015), numerous large scale longitudinal studies demonstrated that subjects who used
marijuana do not have a greater incidence of psychotic diagnoses compared to nonmarijuana users (van Os et al., 2002; Fergusson et al., 2005; Kuepper et al., 2011).
Further, the HHS commented that when analyzing the available data examining the
association between marijuana and psychosis, it is critical to differentiate whether the
patients in a study are already diagnosed with psychosis or if the individuals have a
limited number of symptoms associated with psychosis without qualifying for a diagnosis
of the disorder.

140

 As mentioned by the HHS, some of the studies examining the association between
marijuana and psychosis utilized non-standard methods to categorize psychosis and these
methods did not conform to the criteria in the Diagnostic and Statistical Manual (DSM-5)
or the International Classification of Diseases (ICD-10) and would not be appropriate for
use in evaluating the association between marijuana use and psychosis. For example,
researchers characterized psychosis as “schizophrenic cluster” (Maremmani et al., 2004),
“subclinical psychotic symptoms” (van Gastel et al., 2012), “pre-psychotic clinical high
risk” (van der Meer et al., 2012), and symptoms related to “psychosis vulnerability”
(Griffith-Lendering et al., 2012).
The HHS discussed an early epidemiological study conducted by Andreasson et al.
(1987), which examined the link between psychosis and marijuana use. In this study,
about 45,000 18- and 19-year-old male Swedish subjects provided detailed information
on their drug-taking history and 274 of these subjects were diagnosed with schizophrenia
over a 14-year period (1969 – 1983). Out of the 274 subjects diagnosed with psychosis,
21 individuals (7.7%) had used marijuana more than 50 times, while 197 individuals
(72%) never used marijuana. As presented by the authors (Andreasson et al., 1987),
individuals who claimed to take marijuana on more than 50 occasions were 6 times more
likely to be diagnosed with schizophrenia than those who had never consumed the drug.
The authors concluded that marijuana users who are vulnerable to developing psychoses
are at the greatest risk for schizophrenia. In a 35 year follow up to the subjects evaluated
in Andreasson et al. (1987), Manrique-Garcia et al. (2012) reported similar findings. In
the follow up study, 354 individuals developed schizophrenia. Of those, 32 individuals
(9%) had used marijuana more than 50 times and were 6.3 times more likely to develop
schizophrenia. 255 of the 354 individuals (72%) never used marijuana.
The HHS also noted that many studies support the assertion that psychosis from
marijuana usage may manifest only in individuals already predisposed to development of
psychotic disorders. Marijuana use may precede diagnosis of psychosis (Schimmelmann
et al., 2011), but most reports indicate that prodromal symptoms of schizophrenia are
observed prior to marijuana use (Schiffman et al., 2005). In a review examining geneenvironmental interaction between marijuana exposure and the development of
psychosis, it was concluded that there is some evidence to support that marijuana use
may influence the development of psychosis but only for susceptible individuals (PelayoTeran et al., 2012).
Degenhardt et al. (2003) modeled the prevalence of schizophrenia against marijuana use
across eight birth cohorts in individuals born during 1940 to 1979 in Australia. Even
though there was an increase in marijuana use in the adult subjects over this time period,
there was not an increase in diagnoses of psychosis for these same subjects. The authors
concluded that use of marijuana may increase schizophrenia only in persons vulnerable to
developing psychosis.
Cardiovascular and Autonomic Effects

141

 The HHS stated that acute use of marijuana causes an increase in heart rate (tachycardia)
and may increase blood pressure (Capriotti et al., 1988; Benowitz and Jones, 1975).
There is some evidence that associates the increased heart rate from Δ9-THC exposure
with excitation of the sympathetic and depression of the parasympathetic nervous
systems (Malinowska et al., 2012). Tolerance to tachycardia develops with chronic
exposure to marijuana (Jones, 2002; Sidney, 2002).
Prolonged exposure to Δ9-THC results in a decrease in heart rate (bradycardia) and
hypotension (Benowitz and Jones, 1975). These effects are thought to be mediated
through peripherally located, presynaptic CB1 receptor inhibition of norepinephrine
release with possible direct activation of vascular cannabinoid receptors (Wagner et al.,
1998; Pacher et al., 2006).
As stated in the HHS recommendation (HHS, 2015), marijuana exposure causes
orthostatic hypotension (fainting-like feeling; sudden drop in blood pressure upon
standing up) and tolerance can develop to this effect upon repeated, chronic exposure
(Jones, 2002). Tolerance to orthostatic hypotension is potentially related to plasma
volume expansion, but tolerance does not develop to supine hypotensive effects
(Benowitz and Jones, 1975).
Marijuana smoking, particularly by those with some degree of coronary artery or
cerebrovascular disease, poses risks such as increased cardiac work, increased
catecholamines and carboxyhemoglobin, myocardial infarction and postural hypotension
(Benowitz and Jones, 1981; Hollister, 1988; Mittleman et al., 2001; Malinowska et al.,
2012). However, electrocardiographic changes were minimal after administration of
large cumulative doses of Δ9-THC (Benowitz and Jones, 1975).
The DEA notes two recent reports that reviewed several case studies on marijuana and
cardiovascular complications (Panayiotides, 2015; Hackam, 2015). Panayiotides (2015)
reported that approximately 25.6% of the cardiovascular cases from marijuana use
resulted in death from data provided by the French Addictovigilance Network during the
period of 2006 – 2010. Several case studies on marijuana usage and cardiovascular
events were discussed and it was concluded that although a causal link cannot be
established due to not knowing exact amounts of marijuana used in the cases and
confounding variables, the available evidence supports a link between marijuana and
cardiotoxicity. Hackham (2015) reviewed 34 case reports or case series reports of
marijuana and stroke/ischemia in 64 stroke patients and reported that in 81% of the cases
there was a temporal relationship between marijuana usage and stroke or ischemic event.
The author concluded that collective analysis of the case reports supports a causal link
between marijuana use and stroke.
Respiratory Effects
The HHS stated that transient bronchodilation is the most typical respiratory effect of
acute exposure to marijuana (Gong et al., 1984). In a recent longitudinal study,
information on marijuana use and pulmonary data function were collected from 5,115
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 individuals over 20 years from 4 communities in the United States (Oakland, CA;
Chicago, IL; Minneapolis, MN; Birmingham, AL) (Pletcher et al., 2012). Of the 5,115
individuals, 795 individuals reported use of only marijuana (without tobacco). The
authors reported that occasional use of marijuana (7 joint-years for lifetime or 1 joint/day
for 7 years or 1 joint/week for 49 years) does not adversely affect pulmonary function.
Pletcher et al. (2012) further concluded that there is some preliminary evidence
suggesting that heavy marijuana use may have a detrimental effect on pulmonary
function, but the sample size of heavy marijuana users in the study was too small.
Further, as mentioned in the HHS recommendation document (HHS, 2015), long-term
use of marijuana may lead to chronic cough, increased sputum, as well as increased
frequency of chronic bronchitis and pharyngitis (Adams and Martin, 1996; Hollister,
1986).
The HHS stated that the evidence that marijuana may lead to cancer of the respiratory
system is inconsistent, with some studies suggesting a positive correlation while others
do not (Lee and Hancox, 2011; Tashkin, 2005). The HHS noted a case series that
reported lung cancer occurrences in three marijuana smokers (age range 31 – 37 years)
with no history of tobacco smoking (Fung et al., 1999). Furthermore, in a case-control
study (n = 173 individuals with squamous cell carcinoma of the head and neck; n = 176
controls; Zhang et al., 1999), prevalence of marijuana use was 9.7% in controls and
13.9% in cases and the authors reported that marijuana use may dose-dependently
interact with mutagenic sensitivity, cigarette smoking, and alcohol use to increase risk
associated with head and neck cancers (Zhang et al., 1999). However, in a large clinical
study with 1,650 subjects, no positive correlation was found between marijuana use and
lung cancer (Tashkin et al., 2006). This finding held true regardless of the extent of
marijuana use when both tobacco use and other potential confounding factors were
controlled. The HHS concluded that new evidence suggests that the effects of smoking
marijuana on respiratory function and cancer are different from the effects of smoking
tobacco (Lee and Hancox, 2011).
The DEA further notes the publication of recent review articles critically evaluating the
association between marijuana and lung cancer. Most of the reviews agree that the
association is weak or inconsistent (Huang et al., 2015; Zhang et al., 2015; Gates et al.,
2014; Hall and Degenhardt, 2014). Huang et al. (2015) identified and reviewed six
studies evaluating the association between marijuana use and lung cancer and the authors
concluded that an association is not supported most likely due to the small amounts of
marijuana smoked in comparison to tobacco. Zhang et al. (2015) examined six case
control studies from the US, UK, New Zealand, and Canada within the International
Lung Cancer Consortium and found that there was a weak association between smoking
marijuana and lung cancer in individuals who never smoked tobacco, but precision of the
association was low at high marijuana exposure levels. Hall and Degenhardt (2014)
noted that even though marijuana smoke contains several of the same carcinogens and
co-carcinogens as tobacco smoke (Roth et al., 1998) and has been found to be mutagenic
and carcinogenic in the mouse skin test, epidemiological studies have been inconsistent,
but more consistent positive associations have been reported in case control studies.
Finally Gates et al. (2014), reviewed the studies evaluating marijuana use and lung cancer
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 and concluded that there is evidence that marijuana produces changes in the respiratory
system (precursors to cancer) that could lead to lung cancer, but overall association is
weak between marijuana use and lung cancer especially when controlling for tobacco
use.
Endocrine System
Reproductive Hormones
The HHS stated that administration of marijuana to humans does not consistently alter
the endocrine system. In a controlled human exposure study (n = 4 males), subjects were
acutely administered smoked marijuana containing 2.8% Δ9-THC or placebo and an
immediate significant decrease in luteinizing hormone and an increase in cortisol was
reported in the subjects that smoked marijuana (Cone et al., 1986). Furthermore, as cited
by the HHS, two later studies (Dax et al., 1989; Block et al., 1991) reported no changes in
hormone levels. Dax et al. (1989) recruited male volunteers (n = 17) that were occasional
or heavy users of marijuana. Following exposure to smoked Δ9-THC (18 mg/cigarette)
or oral Δ9-THC (10 mg three times per day for three days and on the morning of the
fourth day), the subjects in that study showed no changes in plasma adrenocorticotropic
hormone (ACTH), cortisol, prolactin, luteinizing hormone, or testosterone levels.
Additionally, Block et al. (1991) compared plasma hormone levels amongst non-users as
well as infrequent, moderate, and frequent users of marijuana (n = 93 men and 56
women) and found that chronic use of marijuana (infrequent, moderate, and frequent
users) did not significantly alter concentrations of testosterone, luteinizing hormone,
follicle stimulating hormone, prolactin, or cortisol.
The HHS noted that there is a discrepancy in the effect of marijuana on female
reproductive system functionality between animals and humans (HHS, 2015). Female
rhesus monkeys that were administered 2.5 mg/kg Δ9-THC, i.m., during days 1 – 18 of
the menstrual cycle had reduced progesterone levels and ovulation was suppressed (Asch
et al., 1981). However, women who smoked marijuana (1 gram marijuana cigarette with
1.8% Δ9-THC) during the periovulatory period (24 – 36 hours prior to ovulation) did not
exhibit changes in reproductive hormone levels or their menstrual cycles (Mendelson and
Mello, 1984). In a review article by Brown and Dobs (2002), the authors state that
endocrine changes observed with marijuana are no longer observed with chronic
administration and this may be due to drug tolerance.
Reproductive Cancers
The HHS stated that recent studies support a possible association between frequent, longterm marijuana use and increased risk of testicular germ cell tumors. In a hospital-based
case-control study, the frequency of marijuana use was compared between testicular germ
cell tumor (TGCT) patients (n = 187) and controls (n = 148) (Trabert et al., 2011).
TGCT patients were more likely to be frequent marijuana users than controls with an
odds ratio (OR) of 2.2 (95% confidence limits of 1.0 – 5.1) and were less likely to be
infrequent or short-term users with odds ratios of 0.5 and 0.6, respectively in comparison
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 to controls (Trabert et al., 2011). The DEA further notes that in two population-based
case-control studies (Daling et al., 2009; Lacson et al., 2012), marijuana use was
compared between patients diagnosed with TGCT and matched controls in Washington
State or Los Angeles County. In both studies, it was reported that TCGT patients were
twice as likely as controls to use marijuana. Authors of both studies concluded that
marijuana use is associated with an elevated risk of TGCT (Daling et al., 2009; Lacson et
al., 2012).
The HHS cited a study (Sarfaraz et al., 2005) demonstrating that WIN 55,212-2 (a mixed
CB1/CB2 agonist) induces apoptosis (one form of cell death) in prostate cancer cells and
decreases expression of androgen receptors and prostate specific antigens, suggesting a
potential therapeutic value for cannabinoid agonists in the treatment of prostate cancer,
an androgen-stimulated type of carcinoma.
Other hormones (e.g. thyroid, appetite)
In more recent studies, as cited by the HHS, chronic marijuana use by subjects (n = 39)
characterized as dependent on marijuana according to the ICD-10 criteria did not affect
serum levels of thyroid hormones: TSH (thyrotropin), T4 (thyroxine), and T3
(triiodothyronine) (Bonnet, 2013). With respect to appetite hormones, in a pilot study
with HIV-positive males, smoking marijuana dose-dependently increased plasma levels
of ghrelin and leptin and decreased plasma levels of peptide YY (Riggs et al., 2012).
The HHS stated that Δ9-THC reduces binding of the corticosteroid dexamethasone in
hippocampal tissue from adrenalectomized rats and acute Δ9-THC releases
corticosterone, with tolerance developing to this effect with chronic administration
(Eldridge et al., 1991). These data suggest that Δ9-THC may interact with the
glucocorticoid receptor system.
Immune System
The HHS stated that cannabinoids alter immune function but that there can be differences
between the effects of synthetic, natural, and endogenous cannabinoids (Croxford and
Yamamura, 2005; Tanasescu and Constantinescu, 2010).
The HHS noted that there are conflicting results in animal and human studies with respect
to cannabinoid effects on immune functioning in subjects with compromised immune
systems. Abrams et al. (2003) examined the effects of marijuana and Δ9-THC in 62 HIV1-infected patients. Subjects received one of three treatments, three times a day:
smoked marijuana cigarette containing 3.95% Δ9-THC, oral tablet containing Δ9-THC
(2.5 mg oral dronabinol), or oral placebo. There were no changes in CD4+ and CD8+
cell counts, HIV RNA levels, or protease inhibitor levels in any of the treatment groups
(Abrams et al., 2003). Therefore, use of cannabinoids showed no short-term adverse
virologic effects in individuals with compromised immune systems. Conversely, Roth et
al. (2005) reported that in immunodeficient mice implanted with human blood cells
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 infected with HIV, exposure to Δ9-THC in vivo suppresses immune function, increases
HIV co-receptor expression, and acts as a cofactor to enhance HIV replication.
The DEA notes two recent clinical studies reporting a decrease in cytokine and
interleukin levels following marijuana use. Keen et al. (2014) compared the differences
in the levels of IL-6 (interleukin-6), a proinflammatory cytokine, amongst non-drug users
(n = 78), marijuana only users (n = 46) and marijuana plus other drug users (n = 45) in a
community-based sample of middle-aged African Americans (Keen et al., 2014). After
adjusting for confounders, analyses revealed that lifetime marijuana only users had
significantly lower IL-6 levels than the nonuser group. Further, Sexton et al. (2014)
compared several immune parameters in healthy individuals and subjects with multiple
sclerosis (MS) and found that the chronic use of marijuana resulted in reduced monocyte
migration, and decreased levels of CCL2 and IL-17 in both healthy and MS groups.
The DEA also notes a review suggesting that Δ9-THC suppresses the immune responses
in experimental animal models and in vitro and that these changes may be primarily
mediated through the CB2 cannabinoid receptor (Eisenstein and Meissler, 2015).
Petitioners’ major comments in relation to Factor 2 and the Government’s
responses
1) The petitioners state that “[m]edical use of cannabis is considered safe.” (Exhibit B,
page 7); and that “[t]here are adequate and well-controlled studies proving the
medical efficacy of cannabis.” (Exhibit B, page 10). The petitioners also allege that
“Cannabis is safer than current, legal Schedule II opiate drugs” and that it presents
milder side effects (Exhibit B, page 9-10).
As detailed in the HHS review and as discussed later in this document (see Factor 3),
there are neither adequate safety studies nor adequate, well-controlled studies proving
marijuana’s efficacy. The DEA notes that neither the CSA nor established scheduling
criteria suggest that the HHS and DEA should consider the relative safety profiles of
drugs when determining the proper schedule. To the extent that the petitioners were
referring to abuse and dependence liability, this document discusses those effects in
factors 1, 4, and 7.
2) The petitioners state that “scientific evidence regarding the safety and efficacy of
cannabis is readily available directly from the National Library of Medicine.”
(Exhibit B, page 14).
The government agrees that many articles discuss marijuana and its constituents. Yet,
these articles in no way demonstrate that marijuana is safe and effective for the treatment
of any disease or condition. As mentioned in the HHS review and as discussed later in
this document (see Factor 3), the current research does not provide adequate detailed
scientific evidence regarding chemistry, pharmacology, toxicology, and effectiveness
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 derived from well-controlled clinical investigations to permit a conclusion that marijuana
is safe and effective for treating a specific, recognized disorder.
3) The petitioners mentioned on page 9 of exhibit B that “[t]here has never been a
lethal overdose of marijuana reported in humans” and that “[t]here is no known
LD50 for any form of cannabis.”
As more fully discussed in Factor 3 below, the HHS and DEA conclude that there are not
adequate studies to determine the safety of marijuana. As discussed in the HHS
document and below, the determination of safety is more complex than a mere
determination of the rate or likelihood of death. Moreover, the lack of overdose deaths
attributed to a drug is not evidence that the drug is safe for medical use.
FACTOR 3: THE STATE OF THE CURRENT SCIENTIFIC KNOWLEDGE
REGARDING THE DRUG OR SUBSTANCE
Chemistry
The HHS stated that marijuana, also known as Cannabis sativa L., is part of the
Cannabaceae plant family and is one of the oldest cultivated crops. The term
“marijuana” is generally used to refer to a mixture of the dried flowering tops and leaves
from Cannabis. Marijuana users primarily smoke the marijuana leaves, but individuals
also ingest marijuana through food infused with marijuana and its extracts. Cannabis
sativa is the primary species of Cannabis that is illegally marketed in the United States.
Marijuana is one of three major derivatives sold as separate illicit products, the other two
being hashish and hash oil. Hashish is composed of the dried and compressed
cannabinoid-rich resinous material of Cannabis and is found as balls and cakes as well as
other forms. Individuals may break off pieces and place them into a pipe to smoke. Hash
oil, a viscous brown or amber colored liquid, is produced by solvent extraction of
cannabinoids from Cannabis and contains approximately 50% cannabinoids. One to two
drops of hash oil on a cigarette has been reported to produce the equivalent of a single
marijuana cigarette (DEA, 2015).
The HHS indicated in its evaluation that the petitioners defined marijuana as including all
Cannabis cultivated strains. However, different marijuana samples are derived from
numerous cultivated strains and may have different chemical compositions including
levels of Δ9-THC and other cannabinoids (Appendino et al., 2011). A consequence of
having different chemical compositions in the various marijuana samples is that there will
be significant differences in safety, biological, pharmacological, and toxicological
profiles and therefore, according to the HHS, all Cannabis strains cannot be considered
collectively because of the variations in chemical composition. Furthermore, the
concentration of Δ9-THC and other cannabinoids present in marijuana may vary due to
growing conditions and processing of the plant after harvesting. For example, the plant
parts collected such as flowers, leaves and stems can influence marijuana’s potency,
quality, and purity (Adams and Martin, 1996; Agurell et al., 1984; Mechoulam, 1973).
Variations in marijuana harvesting have resulted in potencies ranging from a low of 1 to
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 2% up to a high of 17% as indicated by cannabinoid content. The concentration of Δ9THC averages approximately 12% by weight in a typical marijuana mixture of leaves and
stems. However, some specifically grown and selected marijuana samples can contain
15% or greater Δ9-THC (Appendino et al., 2011). As a result, the Δ9-THC content in a 1
gram marijuana cigarette can range from as little as 3 milligrams to 150 milligrams or
more. In a systematic review conducted by Cascini et al. (2012), it was reported that
marijuana’s Δ9-THC content has increased significantly from 1979 – 2009.
Since there is considerable variability in the cannabinoid concentrations and chemical
constituency among marijuana samples, the interpretation of clinical data with marijuana
is complicated. A primary issue is the lack of consistent concentrations of Δ9-THC and
other substances in marijuana which complicates the interpretation of the effects of
different marijuana constituents. An added issue is that the non-cannabinoid components
in marijuana may potentially modify the overall pharmacological and toxicological
properties of various marijuana strains and products.
Various Cannabis strains contain more than 525 identified natural constituents including
cannabinoids, 21 (or 22) carbon terpenoids found in the plant, as well as their carboxylic
acids, analogues, and transformation products (Agurell et al., 1984; 1986; Mechoulam,
1973; Appendino et al., 2011). To date, more than 100 cannabinoids have been
characterized (ElSohly and Slade, 2005; Radwan et al., 2009; Appendino et al., 2011),
and most major cannabinoid compounds occurring naturally have been identified. There
are still new and comparably more minor cannabinoids being characterized (Pollastro et
al., 2011). The majority of the cannabinoids are found in Cannabis. One study reported
accumulation of two cannabinoids, cannabigerol and its corresponding acid, in
Helichrysum (H. umbraculigerum) which is a non-Cannabis source (Appendino et al.,
2011).
Of the cannabinoids found in marijuana, Δ9-THC (previously known as Δ1-THC) and
delta-8-tetrahydrocannabinol (Δ8-THC, Δ6-THC) have been demonstrated to produce
marijuana’s psychoactive effects. Psychoactive effects from marijuana usage have been
mainly attributed to Δ9-THC because Δ9-THC is present in significantly more quantities
than Δ8-THC in most marijuana varieties. There are only a few marijuana strains that
contain Δ8-THC in significant amounts (Hively et al., 1966). Δ9-THC is an optically
active resinous substance that is extremely lipophilic. The chemical name for Δ9-THC is
(6aR-trans)-6a,7,8,10a-tetrahydro-6,6,9-trimethyl-3-pentyl-6H-dibenzo-[b,d]pyran-1-ol,
or (-)-delta9-(trans)-tetrahydrocannabinol. The (-)-trans Δ9-THC isomer is
pharmacologically 6 to 100 times more potent than the (+)-trans isomer (Dewey et al.,
1984).
Other relatively well-characterized cannabinoids present in marijuana include cannabidiol
(CBD), cannabichromene (CBC), and cannabinol (CBN). CBD and CBC are major
cannabinoids in marijuana and are both lipophilic. The chemical name for CBD is 2[(1R,6R)-3-methyl-6-prop-1-en-2-ylcyclohex-2-en-1-yl]-5-pentylbenzene-1,3-diol and
the chemical name for CBC is 2-methyl-2-(4-methylpent-3-enyl)-7-pentyl-5-chromenol.
CBN is a minor naturally-occurring cannabinoid with weak psychoactivity and is also a
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 major metabolite of Δ9-THC. The chemical name for CBN is 6,6,9-trimethyl-3-pentylbenzo[c]chromen-1-ol.
In summary, marijuana has several strains with high variability in the concentrations of
Δ9-THC, the main psychoactive component, as well as other cannabinoids and
compounds. Marijuana is not a single chemical and does not have a consistent and
reproducible chemical profile with predictable or consistent clinical effects. In the HHS
recommendation for marijuana scheduling (HHS, 2015), it was recommended that
investigators consult a guidance for industry entitled, Botanical Drug Products,46 which
provides information on the approval of botanical drug products. Specifically, in order to
investigate marijuana in support of a New Drug Application (NDA), clinical studies
under an Investigational New Drug (IND) application should include “consistent batches
of a particular marijuana product for [a] particular disease.” (HHS, 2015). Furthermore,
the HHS noted that investigators must provide data meeting the requirements for new
drug approval as stipulated in 21 CFR 314.50 (HHS, 2015).
Human Pharmacokinetics
Pharmacokinetics of marijuana in humans is dependent on the route of administration and
formulation (Adams and Martin, 1996; Agurell et al., 1984; Agurell et al., 1986).
Individuals primarily smoke marijuana as a cigarette (weighing between 0.5 and 1 gram)
or in a pipe. More recently, vaporizers have been used as another means for individuals
to inhale marijuana. Marijuana may also be ingested orally in foods or as an extract in
ethanol or other solvents. Pharmacokinetic studies with marijuana focused on evaluating
the absorption, metabolism, and elimination profile of Δ9-THC and other cannabinoids
(Adams and Martin, 1996; Agurell et al., 1984; Agurell et al., 1986).
Absorption and Distribution of Inhaled Marijuana Smoke
There is high variability in the pharmacokinetics of Δ9-THC and other cannabinoids from
smoked marijuana due to differences in individual smoking behavior even under
controlled experimental conditions (Agurell et al., 1986; Herning et al., 1986; Huestis et
al., 1992a). Experienced marijuana users can titrate and regulate the dose by holding
marijuana smoke in their lungs for an extended period of time resulting in increased
psychoactive effects by prolonging absorption of the smoke. This property may also help
explain why there is a poor correlation between venous levels of Δ9-THC and the
intensity of effects and intoxication (Agurell et al., 1986; Barnett et al., 1985; Huestis et
al., 1992a). The HHS recommended that puff and inhalation volumes should be tracked
in experimental studies because the concentration of cannabinoids can vary at different
stages of smoking.
Δ9-THC from smoked marijuana is rapidly absorbed within seconds. Psychoactive
effects are observed immediately following absorption with measurable neurological and
behavioral changes for up to 6 hours (Grotenhermen, 2003; Hollister, 1986; Hollister,
46

Available at http://www.fda.gov/Drugs/default.htm under Guidance (Drugs).

149

 1988). Δ9-THC is distributed to the brain in a rapid and efficient manner. Bioavailability
of Δ9-THC from marijuana (from a cigarette or pipe) ranges from 1 to 24% with the
fraction absorbed rarely exceeding 10 to 20% (Agurell et al., 1986; Hollister, 1988). The
low and variable bioavailability of Δ9-THC is due to loss in side-stream smoke, variation
in individual smoking behaviors and experience, incomplete absorption of inhaled smoke,
and metabolism in lungs (Herning et al., 1986; Johansson et al., 1989). After cessation of
smoking, Δ9-THC venous levels decline within minutes and continue to decline to about
5% to 10% of the peak level within an hour (Agurell et al., 1986; Huestis et al., 1992a;
Huestis et al., 1992b).
Absorption and Distribution of Orally Administered Marijuana
Following oral administration of Δ9-THC or marijuana, onset of effects start within 30 to
90 minutes, peak after 2 to 3 hours and effects remain for 4 to 12 hours (Grotenhermen,
2003; Adams and Martin, 1996; Agurell et al., 1984; Agurell et al., 1986). Dose titration
of Δ9-THC from orally ingested marijuana is difficult for users in comparison to smoked
or inhaled marijuana due to the delay in the onset of effects. Oral bioavailability of Δ9THC, either in its pure form or in marijuana, is low and variable with a range from 5% to
20% (Agurell et al., 1984; Agurell et al., 1986). There is also inter- and intra-subject
variability of orally administered Δ9-THC under experimental conditions and even under
repeated dosing experiments (HHS, 2015). The HHS noted that in bioavailability studies
using radiolabeled Δ9-THC, Δ9-THC plasma levels following oral administration of Δ9THC were low relative to plasma levels after inhaled or intravenously administered Δ9THC. The low and variable bioavailability of orally administered Δ9-THC is due to first
pass hepatic elimination from blood and erratic absorption from stomach and bowel
(HHS, 2015).
Metabolism and Excretion of Cannabinoids from Marijuana
Studies evaluating cannabinoid metabolism and excretion focused on Δ9-THC because it
is the primary psychoactive component in marijuana. Δ9-THC is metabolized via
microsomal hydroxylation and oxidation to both active and inactive metabolites
(Lemberger et al., 1970; Lemberger et al., 1972a; Lemberger et al., 1972b; Agurell et al.,
1986; Hollister, 1988). Metabolism of Δ9-THC is consistent among frequent and
infrequent marijuana users (Agurell et al., 1986). The primary active metabolite of Δ9THC following oral ingestion is 11-hydroxy-Δ9-THC which is equipotent to Δ9-THC in
producing marijuana-like subjective effects (Agurell et al., 1986; Lemberger and Rubin,
1975). Metabolite levels following oral administration may be greater than that of Δ9THC and may contribute greatly to the pharmacological effects of oral Δ9-THC or
marijuana.
Plasma clearance of Δ9-THC approximates hepatic blood flow at a rate of approximately
950 ml/min or greater. Rapid clearance of Δ9-THC from blood is primarily due to
redistribution to other tissues in the body rather than to metabolism (Agurell et al., 1984;
Agurell et al., 1986). Outside of the liver, metabolism in most tissues is considerably
slow or does not occur. The elimination half-life of Δ9-THC ranges from 20 hours to
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 between 10 and 13 days (Hunt and Jones, 1980). Lemberger et al. (1970) reported that
the half-life of Δ9-THC ranged from 23 – 28 hours in heavy marijuana users and up to 60
to 70 hours in naïve users. The long elimination half-life of Δ9-THC is due to slow
release of Δ9-THC and other cannabinoids from tissues and subsequent metabolism.
Inactive carboxy metabolites of Δ9-THC have terminal half-lives of 50 hours to 6 days or
more and serve as long-term markers in urine tests for marijuana use.
Most of the absorbed Δ9-THC dose is eliminated in the feces and about 33% in urine.
The glucuronide metabolite of Δ9-THC is excreted as the major urine metabolite along
with 18 non-conjugated metabolites (Agurell et al., 1986).
Research Status and Test of Currently Accepted Medical Use for Marijuana
According to the HHS, there are numerous human clinical studies with marijuana in the
United States under FDA-regulated IND applications. Results of small clinical
exploratory studies have been published in the medical literature. Approval of a human
drug for marketing, however, is contingent upon FDA approval of a New Drug
Application (NDA) or a Biologics License Application (BLA). According to the HHS,
the FDA has not approved any drug product containing marijuana for marketing.
The HHS noted that a drug may be found to have a medical use in treatment in the United
States for purposes of the CSA if the drug meets the five elements described by the DEA
in 1992. Those five elements “are both necessary and sufficient to establish a prima facie
case of currently accepted medical use” in treatment in the United States.” (57 FR 10499,
10504 (March 26, 1992)). This five-element test, which the HHS and DEA have utilized
in all such analyses for more than two decades, has been upheld by the Court of Appeals.
ACT, 15 F.3d at 1135. The five elements that characterize “currently accepted medical
use” for a drug are summarized here and expanded upon in the discussion below:
1.
2.
3.
4.
5.

The drug’s chemistry must be known and reproducible;
There must be adequate safety studies;
There must be adequate and well-controlled studies proving efficacy;
The drug must be accepted by qualified experts; and
Scientific evidence must be widely available.

In its review (HHS, 2015), the HHS evaluated the five elements with respect to the
currently available research for marijuana. The HHS concluded that marijuana does not
meet any of the five elements – all of which must be demonstrated to find that a drug has
a “currently accepted medical use.” A brief summary of the HHS’s evaluation is
provided below.
Element #1: The drug’s chemistry must be known and reproducible.
“The substance’s chemistry must be scientifically established to permit it to be
reproduced into dosages which can be standardized. The listing of the substance in a
current edition of one of the official compendia, as defined by section 201(j) of the Food,
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 Drug and Cosmetic Act, 21 U.S.C. 321(j), is sufficient generally to meet this
requirement.” 57 Fed. Reg. 10499, 10506 (March 26, 1992).
Marijuana, as defined in the petition, includes all Cannabis strains. (For purposes of the
CSA, marijuana includes all species of the genus Cannabis, including all strains
therein47). Based on the definition of marijuana in the petition, the chemistry of
marijuana is not reproducible such that a standardized dose can be created. Chemical
constituents including Δ9-THC and other cannabinoids vary significantly in marijuana
samples derived from different strains (Appendino et al., 2011). As a result, there will be
significant differences in safety, biological, pharmacological, and toxicological
parameters amongst the various marijuana samples. Due to the variation of the chemical
composition in marijuana samples, it is not possible to reproduce a standardized dose
when considering all strains together. The HHS does advise that if a specific Cannabis
strain is cultivated and processed under controlled conditions, the plant chemistry may be
consistent enough to derive reproducible and standardized doses.
Element #2: There must be adequate safety studies.
“There must be adequate pharmacological and toxicological studies, done by all methods
reasonably applicable, on the basis of which it could fairly and responsibly be concluded,
by experts qualified by scientific training and experience to evaluate the safety and
effectiveness of drugs, that the substance is safe for treating a specific, recognized
disorder.” 57 Fed. Reg. 10499, 10506 (March 26, 1992).
The HHS stated that there are no adequate safety studies on marijuana. As indicated in
their evaluation of Element #1, the considerable variation in the chemistry of marijuana
complicates the safety evaluation. The HHS concluded that marijuana does not satisfy
Element #2 for having adequate safety studies such that medical and scientific experts
may conclude that it is safe for treating a specific ailment.
Element #3: There must be adequate and well-controlled studies of efficacy.
“There must be adequate, well-controlled, well-designed, well-conducted and welldocumented studies, including clinical investigations, by experts qualified by scientific
training and experience to evaluate the safety and effectiveness of drugs, on the basis of
which it could be fairly and responsibly concluded by such experts that the substance will

47

Although the CSA definition of marijuana refers only to the species "Cannabis sativa L.," federal courts
have consistently ruled that all species of the genus cannabis are included in this definition. See United
States v. Kelly, 527 F.2d 961, 963-964 (9th Cir. 1976) (collecting and examining cases). The Single
Convention (article 1, par. 1(c)) likewise defines the "cannabis plant" to mean "any plant of the genus
Cannabis." As explained above in the attachment titled "Preliminary Note Regarding Treaty
Considerations," 21 U.S.C. 811(d)(1) provides that, where a drug is subject to control under the Single
Convention, the DEA Administrator must control the drug under the schedule he deems most appropriate to
carry out such treaty obligations, without regard to the findings required by 21 U.S.C. 811(a) or 812(b) and
without regard to the procedures prescribed by 21 U.S.C. 811(a) and (b).

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 have the intended effect in treating a specific, recognized disorder.” 57 Fed. Reg. 10499,
10506 (March 26, 1992).
As indicated in the HHS’s review of marijuana (HHS, 2015), there are no adequate or
well-controlled studies that prove marijuana’s efficacy. The FDA independently
reviewed (FDA, 2015) publicly available clinical studies on marijuana published prior to
February 2013 to determine if there were appropriate studies to determine marijuana’s
efficacy (please refer to FDA, 2015 and HHS, 2015 for more details). After review, the
FDA determined that out of the identified articles, including those identified through a
search of bibliographic references and 566 abstracts located on PubMed, 11 studies met
the a priori selection criteria, including placebo control and double-blinding. FDA and
HHS critically reviewed each of the 11 studies to determine if the studies met accepted
scientific standards. FDA and HHS concluded that these studies do not “currently prove
efficacy of marijuana” for any therapeutic indication due to limitations in the study
designs. The HHS indicated that these studies could be used as proof of concept studies,
providing preliminary evidence on a proposed hypothesis involving a drug’s effect.
Element #4: The drug must be accepted by qualified experts.
“[A] consensus of the national community of experts, qualified by scientific training and
experience to evaluate the safety and effectiveness of drugs, accepts the safety and
effectiveness of the substance for use in treating a specific, recognized disorder. A
material conflict of opinion among experts precludes a finding of consensus.” 57 Fed.
Reg. 10499, 10506 (March 26, 1992).
The HHS concluded that there is currently no evidence of a consensus among qualified
experts that marijuana is safe and effective in treating a specific and recognized disorder.
The HHS indicated that medical practitioners who are not experts in evaluating drugs
cannot be considered qualified experts (HHS, 2015; 57 FR 10499, 10505). Further, the
HHS noted that the 2009 American Medical Association (AMA) report entitled, “Use of
Cannabis for Medicinal Purposes” does not conclude that there is a currently accepted
medical use for marijuana. HHS also pointed out that state-level “medical marijuana”
laws do not provide evidence of such a consensus among qualified experts.
Element #5: The scientific evidence must be widely available.
“In the absence of NDA approval, information concerning the chemistry, pharmacology,
toxicology, and effectiveness of the substance must be reported, published, or otherwise
widely available, in sufficient detail to permit experts, qualified by scientific training and
experience to evaluate the safety and effectiveness of drugs, to fairly and responsibly
conclude the substance is safe and effective for use in treating a specific, recognized
disorder.” 57 Fed. Reg. 10499, 10506 (March 26, 1992).
The HHS concluded that the currently available data and information on marijuana is not
sufficient to allow scientific scrutiny of the chemistry, pharmacology, toxicology, and
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 effectiveness. In particular, scientific evidence demonstrating the chemistry of a specific
Cannabis strain that could provide standardized and reproducible doses is not available.
Petitioners’ major comments in relation to Factor 3 and the Government’s
responses
1) The petitioners indicate that there is medical support and acceptance for the medical
use of marijuana and stated that “[c]annabis has been accepted by the medical
community as meeting the current, modern accepted standards for what constitutes
medicine.” (Exhibit B, page 13). On page 3 of the cover letter of the petition, the
petitioners stated, “The American medical community supports rescheduling, and
there are safe pharmacy-based methods to dispense medical cannabis.”
Furthermore, they stated that “[i]n 2009, the American Medical Association (AMA)
reversed its earlier position that supported [s]chedule I classification of cannabis.
The AMA now supports investigation and clinical research of cannabis for medicinal
use, and urged the federal government to reassess the [s]chedule I classification. The
American College of Physicians [ACP] recently expressed similar support.” In
addition, they note that the Institute of Medicine (IOM) also documented the
scientific basis and therapeutic effects of cannabis (Exhibit B, page 13).
The DEA notes that the statements by the cited organizations (AMA, ACP, IOM) support
more research into the potential medical properties associated with marijuana. The HHS
did not find that the statements by these organizations provide evidence supporting a
conclusion that adequate safety studies and adequate, well-controlled efficacy studies
demonstrate the safety and efficacy of marijuana (HHS, 2015). The AMA’s official
policy on medicinal use of marijuana is as follows: “Our AMA urges that marijuana’s
status as a federal [s]chedule I controlled substance be reviewed with the goal of
facilitating the conduct of clinical research and development of cannabinoid-based
medicines, and alternative delivery methods. This should not be viewed as an
endorsement of state-based medical cannabis programs, the legalization of marijuana, or
that scientific evidence on the therapeutic use of cannabis meets the current standards for
a prescription drug product.” (AMA, 2009).
The DEA further notes that the 2013 AMA House of Delegates report states that,
“cannabis is a dangerous drug and as such is a public health concern.” (AMA, 2013).
In 2008, the ACP indicated that “further research is needed to compare cannabinoids’
efficacy and safety with current treatments.” (ACP, 2008). The ACP stated that, “ACP
urges an evidence-based review of marijuana’s status as a [s]chedule I controlled
substance to determine whether it should be reclassified to a different schedule. This
review should consider the scientific findings regarding marijuana’s safety and efficacy
in some clinical conditions as well as evidence on the health risks associated with
marijuana consumption, particularly in its crude smoked form” (ACP, 2008). The IOM,
consistent with others in the medical community, endorses further studies into the
potential therapeutic uses of marijuana, but did not advocate for medicinal use without
further testing (IOM, 2009).
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 As detailed in the HHS review, in order for a drug to be found to have a “currently
accepted medical use,” it must be accepted by qualified experts. There is no evidence
that there is a consensus among qualified experts that marijuana is safe and effective for
use in treating a specific, recognized disorder.
2) The petitioners claim that, “The chemistry of cannabis is known and reproducible”
(Exhibit B, page 6) and “newer medicinal strains of cannabis are lower in THC and
higher in the non-psychoactive, more therapeutic cannabinoids, such as CBD, and
CBN. These compounds further improved the efficacy of cannabis.” (Exhibit B, page
10).
As indicated by the HHS, the petitioners defined marijuana to include all Cannabis
strains. As such, the chemistry of marijuana is not reproducible such that a standardized
dose can be created. Chemical constituents including Δ9-THC and other cannabinoids
vary significantly in different marijuana samples (Appendino et al., 2011). Furthermore,
the HHS cited a published report that indicates that new substances in marijuana are
continually being characterized (Pollastro et al., 2011). If there is significant variance in
the chemical composition of marijuana between samples, it is not possible for the
chemistry to be reproducible.
Because the petition defines marijuana as including all cultivated strains, the DEA
believes that the THC and CBD level of specific strains is not relevant to this
consideration. In fact, the average Δ9-THC content in marijuana has steadily risen from
1995 to 2014 as reported by the University of Mississippi Potency Monitoring Project, as
presented in Factor 1. In 1995, the Δ9-THC content was 4% on average and by 2015, the
average content of THC had risen to 11.2% over a 20 year period. In the same time
period, CBD and CBN percentages have ranged from 0.15% to 0.60% on average.
The DEA also notes statements in the petitioners’ document that support the conclusion
reached by DEA and HHS that the chemistry of marijuana as broadly defined by the
petitioners is not reproducible or well-defined. For example, the petitioners acknowledge
that “Cannabis is a complex plant, with several subtypes of cannabis.” (Exhibit B, page
6). The petitioners also acknowledge that “the ratios of the various cannabinoids differ
according to the plant strain, and, to some extent, how the plant is grown.” (Exhibit B,
page 12).
3) The petitioners stated in Exhibit B, page 8, that “[o]verall, the 33 completed and
published American controlled clinical trials with cannabis have studied its safety,
routes of administration, and use in comparison with placebos, standard drugs, and
in some cases dronabinol…,” and further cited a systematic review by Wang et al.
(2008), that evaluated 23 randomized controlled trials and 8 observational studies,
stating that, “[o]f all the adverse events reported, 97 percent were considered ‘not
serious,’ with the most commonly reported ‘dizziness.’”

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 The petitioners also cited in Exhibit B, page 8, “There has been a long-term,
prospective, federally funded cannabis clinical study jointly administered by National
Institute on Drug Abuse (NIDA) and FDA. This study has been running for over 30
years without any demonstrable adverse outcomes related to chronic medicinal
cannabis use.”
As cited in the HHS recommendation document (HHS, 2015), the FDA conducted its
own evaluation of the published clinical studies on the medical application of marijuana
prior to February 2013 (FDA, 2015). Further details on the FDA review can be found in
the published report (FDA, 2015). Based on the analysis, 11 studies were evaluated
further and the FDA concluded that none of these studies “meet the criteria required by
the FDA to determine if marijuana is safe and effective in specific therapeutic areas.”
(page 6; FDA, 2015).
The DEA has reviewed the systematic review by Wang et al. (2008) and notes that most
of the studies included in the review were synthetic cannabinoid medicines (e.g.
dronabinol) or cannabinoid extracts (e.g. Sativex®); these types of studies were excluded
in the FDA review as the analysis focused solely on natural forms of marijuana (FDA,
2015). Wang et al. (2008) concluded that “good safety and efficacy data on smoked
cannabis are urgently needed.”
With respect to the 30-year study cited by the petitioners (Russo et al., 2001) on page 8 of
Exhibit B, it should be clarified that the referenced study was not jointly administered by
NIDA and the FDA. As with other clinical studies, an IND application was approved by
the FDA and marijuana was supplied by NIDA. The authors evaluated only 8 patients
over this period, of which one patient died. While the findings cited by the petitioners
and authors (e.g. no adverse outcomes with long term marijuana use) are informative,
conclusions on long-term use of marijuana cannot be applied to the general population.
FACTOR 4: ITS HISTORY AND CURRENT PATTERN OF ABUSE
Marijuana continues to be the most widely used illicit drug. In 2013, an estimated 24.6
million Americans age 12 or older were current (past month) illicit drug users. Of those,
19.8 million were current (past month) marijuana users. As of 2013, an estimated 114.7
million Americans age 12 and older had used marijuana or hashish in their lifetime and
33.0 million had used it in the past year.
According to the NSDUH estimates, 3.0 million people age 12 or older used an illicit
drug for the first time in 2014. Marijuana initiates totaled 2.6 million in 2014. Nearly
half (46.8%) of the 2.6 million new users were less than 18 years of age. In 2014,
marijuana was used by 82.2% of current (past month) illicit drug users. In 2014, among
past year marijuana users age 12 or older, 18.5% used marijuana on 300 or more days
within the previous 12 months. This translates into 6.5 million people using marijuana on
a daily or almost daily basis over a 12-month period, a significant increase from the 3.1
million daily or almost daily users in 2006 and from the 5.7 million in just the previous
year. In 2014, among past month marijuana users, 41.6% (9.2 million people) used the
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 drug on 20 or more days in the past month, a significant increase from the 8.1 million in
2013.
Marijuana is also the illicit drug with the highest numbers of past year dependence or
abuse in the US population. According to the 2014 NSDUH report, of the 7.1 million
persons aged 12 or older who were classified with illicit drug dependence or abuse, 4.2
million of them abused or were dependent on marijuana (representing 59.0% of all those
classified with illicit drug dependence or abuse and 1.6% of the total U.S. noninstitutionalized population aged 12 or older).
According to the 2015 Monitoring the Future (MTF) survey, marijuana is used by a large
percentage of American youths, and is the most commonly used illicit drug among
American youth. Among students surveyed in 2015, 15.5% of 8th graders, 31.1% of 10th
graders, and 44.7% of 12th graders reported that they had used marijuana in their lifetime.
In addition, 11.8%, 25.4%, and 34.9% of 8th, 10th, and 12th graders, respectively, reported
using marijuana in the past year. A number of high school students reported daily use in
the past month, including 1.1%, 3.0%, and 6.0% of 8th, 10th, and 12th graders,
respectively.
The prevalence of marijuana use and abuse is also indicated by criminal investigations
for which drug evidence was analyzed in federal, state, and local forensic laboratories, as
discussed above in Factor 1. The National Forensic Laboratory System (NFLIS), a DEA
program, systematically collects drug identification results and associated information
from drug cases submitted to and analyzed by federal, state, and local forensic
laboratories. NFLIS data shows that marijuana was the most frequently identified drug
from January 2001 through December 2014. In 2014, marijuana accounted for 29.3%
(432,989) of all drug exhibits in NFLIS.
The high consumption of marijuana is being fueled by increasing amounts of
domestically grown marijuana as well as increased amounts of foreign source marijuana
being illicitly smuggled into the United States. In 2014, the Domestic Cannabis
Eradication and Suppression Program (DCE/SP) reported that 3,904,213 plants were
eradicated in outdoor cannabis cultivation areas compared to 2,597,798 in 2000, as
shown above in Table 3. Significant quantities of marijuana were also eradicated from
indoor cultivation operations. There were 396,620 indoor plants eradicated in 2014
compared to 217,105 eradicated in 2000. As shown in Table 2 above, in 2014, the
National Seizure System (NSS) reported seizures of 1,767,741 kg of marijuana.
Petitioners’ major comments in relation to Factor 4 and the Government’s
responses
1) The petitioners indicated that the history and current pattern of abuse is difficult
to estimate since “a large percentage of United States citizens” have used
marijuana at least once in their lifetime and some estimates have indicated that
“over 40 percent of the nation has tried the plant.” Further, the petitioners stated
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 that “trying marijuana once should not be confused with a health problem, let
alone a diagnosis of dependence or abuse.” (Exhibit B, page 26).
Marijuana usage numbers mentioned in both the HHS Recommendation and this DEA
document include surveys from NSDUH and MTF. These surveys measure extent of use
of marijuana. As mentioned in this Factor, according to the results of the 2013 NSDUH
survey, 17.4% of past year marijuana users age 12 or older used marijuana on 300 or
more days within the previous 12 months. This indicates that 5.7 million people used
marijuana on a daily or almost daily basis over this 12-month period, which is a 1.8-fold
increase from the 3.1 million daily or almost daily users in 2006. Furthermore, 6% of all
twelfth graders in the United States reported daily use of marijuana in the 2015 MTF
survey. These data strongly indicate that there is a significant portion of the U.S.
population using marijuana on a daily basis.
2) As stated in Exhibit B on page 26, subpart A, “Rates of dependence or abuse are
remarkably low” and further suggest that “[i]nterviews for the National
Longitudinal Alcohol Epidemiological Survey ([NLAES] [sic] and National
Epidemiological Survey on Alcohol and Related Conditions ([NESARC] [sic]
each confirm that rates of dependence or abuse of cannabis have never exceed
(sic) two percent in a given year.”
The authors of study cited by the petitioners (Compton et al., 2004) concluded that a
higher percentage of American adults had a marijuana use disorder in 2001 – 2002
(1.5%) than in 1991 – 1992 (1.2%). Compton et al. (2004) noted that the marijuana use
disorder increase of 0.3% over the 10 year period would equate to an increase from 2.2
million people to 3 million people in the United States. The petitioners failed to explain
the impact of 1.5% (or less than 2 percent) of the U.S. population having a marijuana use
disorder. In order to put these numbers into perspective, the DEA reviewed the literature
and found that non-medical prescription drug use and abuse rates were examined in the
same NLAES and NESARC (1991 – 1992 and 2001 – 2002) populations (Blanco et al.,
2007). Blanco et al (2007) examined non-medical prescription drug use and abuse rates
from the periods of 1991 – 1992 and 2001 – 2002. In 1991 through 1992, the prevalence
of non-medical prescription drug (opioid, stimulant, and tranquilizer) abuse and
dependence was 0.1%. Non-medical prescription drug (primarily opioid-based drugs)
abuse and dependence increased to 0.3% in 2001 through 2002. Therefore, in the same
2001 – 2002 NLAES and NESARC populations, the percentage of people with a
marijuana use disorder was approximately five-fold higher (1.5% versus 0.3%) than those
with opioid abuse and dependence resulting from non-medical prescription drug use.
Further, Volkow et al. (2014) reported that in long-term or heavy marijuana users, 9% of
users become addicted to marijuana. This percentage increases to 17% when marijuana
use starts in adolescence and it increases to 25 to 50% of those who are daily users.

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 FACTOR 5: THE SCOPE, DURATION, AND SIGNIFICANCE OF ABUSE
Abuse of marijuana is widespread and significant. As previously noted, according to the
NSDUH, in 2014, an estimated 117.2 million Americans (44.2%) age 12 or older had
used marijuana or hashish in their lifetime, 35.1 million (13.2%) had used it in the past
year, and 22.2 million (8.4%) had used it in the past month. Past year and past month
marijuana use has increased significantly since 2013. Past month marijuana use is
highest among 18-21 year olds and it declines among those 22 years of age and older. In
2014, an estimated 18.5% of past year marijuana users age 12 or older used marijuana on
300 or more days within the past 12 months. This translates into 6.5 million persons
using marijuana on a daily or almost daily basis over a 12-month period. In 2014, an
estimated 41.6% (9.2 million) of past month marijuana users age 12 or older used the
drug on 20 or more days in the past month (SAMHSA, NSDUH). Chronic use of
marijuana is associated with a number of health risks (see Factors 2 and 6).
Furthermore, the average percentage of Δ9-THC in seized marijuana has increased over
the past two decades (The University of Mississippi Potency Monitoring Project).
Additional studies are needed to clarify the impact of greater potency, but one study
shows that higher levels of Δ9-THC in the body are associated with greater psychoactive
effects (Harder and Rietbrock, 1997), which can be correlated with higher abuse potential
(Chait and Burke, 1994).
TEDS data show that in 2013, marijuana/hashish was the primary substance of abuse in
16.8% of all admissions to substance abuse treatment among patients age 12 and older.
TEDS data also show that marijuana/hashish was the primary substance of abuse for
77.0% of all 12- to 14-year-olds admitted for drug treatment and 75.5% of all 15- to 17year-olds admitted for drug treatment in 2013. Among the 281,991 admissions to drug
treatment in 2013 in which marijuana/hashish was the primary drug, the average age at
admission was 25 years and the peak age cohort was 15 to 17 years (22.5%). Thirty-nine
percent of the 281,991 primary marijuana/hashish admissions (35.9%) were under the age
of 20.
In summary, the recent statistics from these various surveys and databases (see Factor 1
for more details) demonstrate that marijuana continues to be the most commonly used
illicit drug, with large incidences of heavy use and dependence in teenagers and young
adults.
Petitioners’ major comment in relation to Factor 5 and DEA’s response
1) Petitioners’ contend that, “The prevalence and significance of potential abuse
are limited for cannabis, especially in relation to other [s]chedule II
substances.” The petitioners cited results from the 1990 NIDA Household
Survey on Drug Abuse and indicated that, “more than four out of five people
who had used cannabis in the previous year reported no problems related to
the drug.” (Exhibit B, page 28).
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 The prevalence of marijuana usage and marijuana dependence is significant in the United
States. The 2014 NSDUH findings indicate that there are approximately 6.5 million
Americans using marijuana on a daily or almost daily basis. Further,Volkow et al. (2014)
reported that in long-term or heavy marijuana users, 9% of users become addicted to
marijuana. Among those who began using marijuana in adolescence, marijuana
dependence increases to 17%, and it further increases to 25 to 50% of daily users that
started using marijuana during adolescence. These collective findings indicate that there
is considerable significance associated with marijuana use and abuse since 9% of users
become addicted to marijuana, 25 to 50% of daily marijuana users started during
adolescence, and prevalence of usage is significantly high based on the data presented
from Volkow et al (2014) and the 2014 NSDUH survey.
FACTOR 6: WHAT, IF ANY, RISK THERE IS TO THE PUBLIC HEALTH
In its recommendation, the HHS discussed public health risks associated with acute and
chronic marijuana use in Factor 6. Public health risks as measured by emergency
department visits and drug treatment admissions are discussed by HHS and DEA in
Factors 1, 4, and 5. Similarly, Factor 2 discusses marijuana’s pharmacology and presents
some of the adverse health effects associated with use. Marijuana use may affect the
physical and/or psychological functioning of an individual user, but may also have
broader public impacts including driving impairments and fatalities from car accidents.
Risks from Acute Use of Marijuana
As discussed in the HHS review document (HHS, 2015), acute usage of marijuana
impairs psychomotor performance including motor control and impulsivity, risk taking
and executive function (Ramaekers et al., 2004; Ramaekers et al., 2006). In a minority of
individuals using marijuana, dysphoria, prolonged anxiety, and psychological distress
may be observed (Haney et al., 1999). The DEA further notes a recent review of acute
marijuana effects (Wilkinson et al., 2014) that reported impaired neurological function
including altered perception, paranoia, delayed response time, and memory deficits.
In its recommendation, HHS references a meta-analysis conducted by Li et al (2012)
where the authors concluded that psychomotor impairments associated with acute
marijuana usage have also been associated with increased risk of car accidents with
individuals experiencing acute marijuana intoxication (Li et al., 2012; HHS, 2015). The
DEA further notes more recent studies examining the risk associated with marijuana use
and driving. Younger drivers (under 21) have been characterized as the highest risk
group associated with marijuana use and driving (Whitehill et al., 2014). Furthermore, in
2013, marijuana was found in 13% of the drivers involved in automobile-related fatal
accidents (McCartt, 2015). The potential risk of automobile accidents associated with
marijuana use appears to be increasing since there has been a steady increase in
individuals intoxicated with marijuana over the past 20 years (Wilson et al., 2014).
However, a recent study commissioned by the National Highway Traffic Safety
Administration (NHTSA) reported that when adjusted for confounders (e.g., alcohol use,
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 age, gender, ethnicity), there was not a significant increase in crash risk (fatal and
nonfatal, n = 2,682) associated with marijuana use (Compton and Berning, 2015).
The DEA also notes recent studies examining unintentional exposures of children to
marijuana (Wang et al., 2013; 2014). Wang et al. (2013) reviewed emergency
department (ED) visits at a children’s hospital in Colorado from January 1, 2005 to
December 31, 2011. As stated by the authors, in 2000 Colorado passed Amendment 20
which allowed for the use of marijuana. Following the passage of “a new Justice
Department policy” instructing “federal prosecutors not to seek arrest of medical
marijuana users and suppliers as long as they conform to state laws” (as stated in Wang et
al., 2013), 14 patients in Colorado under the age of 12 were admitted to the ED for the
unintended use of marijuana over a 27 month period. Prior to the passage of this policy,
from January 1, 2005 to September 30, 2009 (57 months), there were no pediatric ED
visits due to unintentional marijuana exposure (Wang et al., 2013). The DEA also notes a
larger scale evaluation of pediatric exposures using the National Poison Data System
(Wang et al., 2014). That study reported that there were 985 unintentional marijuana
exposures in children (9 years and younger) between January 1, 2005 to December 31,
2011. The authors stratified the ED visits by states with laws allowing medical use of
marijuana, states transitioning to legalization for medical use, and states with no such
laws. Out of the 985 exposures, 495 were in non-legal states (n=33 states), 93 in
transitional states (n=8 states), and 396 in “legal” states (n=9 states). The authors
reported that there was a twofold increase (OR = 2.1) in moderate or major effects in
children with unintentional marijuana use and a threefold increase (OR = 3.4) in
admissions to critical care units in states allowing medical use of marijuana, in
comparison to non-legal states.
Risks Associated with Chronic Use of Marijuana
The HHS noted that a major risk from chronic marijuana use is a distinctive withdrawal
syndrome, as described in the 2013 DSM-5. The HHS analysis also quoted the following
description of risks associated with marijuana [cannabis] abuse from the DSM-5:
Individuals with cannabis use disorder may use cannabis throughout the
day over a period of months or years, and thus may spend many hours a
day under the influence. Others may use less frequently, but their use
causes recurrent problems related to family, school, work, or other
important activities (e.g., repeated absences at work; neglect of family
obligations). Periodic cannabis use and intoxication can negatively affect
behavioral and cognitive functioning and thus interfere with optimal
performance at work or school, or place the individual at increased
physical risk when performing activities that could be physically
hazardous (e.g. driving a car; playing certain sports; performing manual
work activities, including operating machinery). Arguments with spouses
or parents over the use of cannabis in the home, or its use in the presence
of children, can adversely impact family functioning and are common
features of those with cannabis use disorder. Last, individuals with
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 cannabis use disorder may continue using marijuana despite knowledge of
physical problems (e.g. chronic cough related to smoking) or
psychological problems (e.g. excessive sedation or exacerbation of other
mental health problems) associated with its use. (HHS 2015, page 34).
The HHS stated that chronic marijuana use produces acute and chronic adverse effects on
the respiratory system, memory and learning. Regular marijuana smoking can produce a
number of long-term pulmonary consequences, including chronic cough and increased
sputum (Adams and Martin, 1996), and histopathologic abnormalities in bronchial
epithelium (Adams and Martin, 1996).
Marijuana as a “Gateway Drug”
The HHS reviewed the clinical studies evaluating the gateway hypothesis in marijuana
and found them to be limited. The primary reasons were: 1) recruited participants were
influenced by social, biological, and economic factors that contribute to extensive drug
abuse (Hall and Lynskey, 2005), and 2) most studies testing the gateway drug hypothesis
for marijuana use the determinative measure any use of an illicit drug rather than
applying DSM-5 criteria for drug abuse or dependence (DSM-5, 2013).
The HHS cited several studies where marijuana use did not lead to other illicit drug use
(Kandel and Chen, 2000; von Sydow et al., 2002; Nace et al., 1975). Two separate
longitudinal studies with adolescents using marijuana did not demonstrate an association
with use of other illicit drugs (Kandel and Chen, 2000; von Sydow et al., 2002).
It was noted by the HHS that, when evaluating the gateway hypothesis, differences
appear when examining use versus abuse or dependence of other illicit drugs. Van
Gundy and Rebellon (2010) reported that there was a correlation between marijuana use
in adolescence and other illicit drug use in early adulthood, but when examined in terms
of drug abuse of other illicit drugs, age-linked stressors and social roles were confounders
in the association. Degenhardt et al. (2009) reported that marijuana use often precedes
use of other illicit drugs, but dependence involving drugs other than marijuana frequently
correlated with higher levels of illicit drug abuse. Furthermore, Degenhardt et al. (2010)
reported that in countries with lower prevalence of marijuana usage, use of other illicit
drugs before marijuana was often documented.
Based on these studies among others, the HHS concluded that although many individuals
with a drug abuse disorder may have used marijuana as one of their first illicit drugs, this
does not mean that individuals initiated with marijuana inherently will go on to become
regular users of other illicit drugs.
Petitioners’ Major Comment in Relation to Factor 6 and the Government’s
Responses

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 1) The petitioners commented that marijuana does not significantly impact social
behavior in domains such as motivation, driving, aggression, or hostility (Exhibit
B, pages 30-41).
The HHS concluded that “Marijuana's acute effects can significantly interfere with a
person's ability … to operate motor vehicles.” (HHS, 2015) As mentioned in this factor,
there is a significant risk with marijuana use and driving. Marijuana was found in 13% of
drivers involved in automobile fatal accidents (McCartt, 2015). Furthermore, in a metaanalysis conducted by Li et al. (2011), an association was identified between marijuana
use by the driver and an increased risk of getting into a car accident.
The DEA notes that the petitioners only considered whether marijuana creates social
problems, and did not consider physiological changes and impacts that also should be
evaluated in determining the risk to public health. The HHS and DEA considered the
public health impacts of such physiological effects, as discussed in this factor and others
above. Marijuana may result in acute cardiovascular toxicity as indicated by recent
reviews examining these associations (Hackham, 2015; Panayiotides, 2015). There is a
possible association between frequent, long-term marijuana use and increased risk of
testicular germ cell cancers and some evidence that chronic marijuana use may lead to
lung cancer although the evidence is inconsistent. Furthermore, a more recent risk is the
increase in ED visits of children unintentionally exposed to marijuana with increased risk
factors for major adverse effects or admission to critical care units in states that have
legalized marijuana for medical purposes (Wang et al., 2014).
FACTOR 7: ITS PSYCHIC OR PHYSIOLOGICAL DEPENDENCE LIABILITY
Physiological (Physical) Dependence in Humans
The HHS stated that heavy and chronic use of marijuana can lead to physical dependence
(DSM-5, 2013; Budney and Hughes, 2006; Haney et al., 1999). Tolerance is developed
following repeated administration of marijuana and withdrawal symptoms are observed
as following discontinuation of marijuana usage (HHS, 2015).
The HHS mentioned that tolerance can develop to some of marijuana’s effects, but does
not appear to develop with respect to the psychoactive effects. It is believed that lack of
tolerance to psychoactive effects may relate to electrophysiological data demonstrating
that chronic Δ9-THC administration does not affect increased neuronal firing in the
ventral tegmental area, a brain region that plays a critical role in drug reinforcement and
reward (Wu and French, 2000). Humans can develop tolerance to marijuana’s
cardiovascular, autonomic, and behavioral effects (Jones et al., 1981). Tolerance to some
behavioral effects appears to develop with heavy and chronic use, but not with occasional
usage. Ramaekers et al. (2009) reported that following acute administration of
marijuana, occasional marijuana users still exhibited impairments in tracking and
attention tasks whereas performance of heavy users on the these tasks was not affected.
In a follow-up study with the same subjects that participated in the study by Ramaekers et
al. (2009), a neurophysiological assessment was conducted where event-related potentials
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 (ERPs) were measured using electroencephalography (EEG) (Theunissen et al., 2012).
Similar to the earlier results, the heavy marijuana users (n = 11; average of 340 marijuana
uses per year) had no changes in their ERPs with the acute marijuana exposure.
However, occasional users (n = 10; average of 55 marijuana uses per year) had
significant decreases in the amplitude of an ERP component (categorized as P100) on
tracking and attention tasks and ERP amplitude change is indicative of a change in brain
activity (Theunissen et al., 2012).
The HHS indicated that down-regulation of cannabinoid receptors may be a possible
mechanism for tolerance to marijuana’s effects (Hirvonen et al., 2012; Gonzalez et al.,
2005; Rodriguez de Fonseca et al., 1994; Oviedo et al., 1993).
As indicated by the HHS, the most common withdrawal symptoms in heavy, chronic
marijuana users are sleep difficulties, decreased appetite or weight loss, irritability, anger,
anxiety or nervousness, and restlessness (Budney and Hughes, 2006; Haney et al., 1999).
As reported by HHS, most marijuana withdrawal symptoms begin within 24 – 48 hours
of discontinuation, peak within 4 – 6 days, and last for 1 – 3 weeks.
The HHS pointed out that the American Psychiatric Association’s (APA’s) Diagnostic
and Statistical Manual of Mental Disorders-5 (DSM-5) included a list of withdrawal
symptoms following marijuana [cannabis] use (DSM-5, 2013). The DEA notes that a
DSM-5 working group report indicated that marijuana withdrawal symptoms were added
to DSM-5 (they were not previously included in DSM-IV) because marijuana withdrawal
has now been reliably presented in several studies (Hasin et al., 2013). In short,
marijuana withdrawal signs are reported in up to one-third of regular users and between
50% and 90% of heavy users (Hasin et al., 2013). According to DSM-5 criteria, in order
to be characterized as having marijuana withdrawal, an individual must develop at least
three of the seven symptoms within one week of decreasing or stopping the heavy and
prolonged use (DSM-5, 2013). These seven symptoms are: 1) irritability; anger or
aggression, 2) nervousness or anxiety, 3) sleep difficulty, 4) decreased appetite or weight
loss, 5) restlessness, 6) decreased mood, 7) somatic symptoms causing significant
discomfort (DSM-5, 2013).
Psychological (Psychic) Dependence in Humans
High levels of psychoactive effects such as positive reinforcement correlate with
increased marijuana abuse and dependence (Scherrer et al., 2009; Zeiger et al., 2010).
Epidemiological marijuana use data reported by NSDUH, MTF, and TEDS support this
assertion as presented in the HHS 2015 review of marijuana and updated by the DEA.
According to the findings in the 2014 NSDUH survey, an estimated 9.2 million
individuals 12 years and older used marijuana daily or almost daily (20 or more days
within the past month). In the 2015 MTF report, daily marijuana use (20 or more days
within the past 30 days) in 8th, 10th, and 12th graders is 1.1%, 3.0%, and 6.0%,
respectively.

164

 The 2014 NSDUH report stated that 4.2 million persons were classified with dependence
on or abuse of marijuana in the past year (representing 1.6% of the total population age
12 or older, and 59.0% of those classified with illicit drug dependence or abuse) based on
criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition
(DSM-IV). Furthermore, of the admissions to licensed substance abuse facilities, as
presented in TEDS, marijuana/hashish was the primary substance of abuse for; 18.3%
(352,297) of 2011 admissions; 17.5% (315,200) of 2012 admissions; and 16.8%
(281,991) of 2013 admissions. Of the 281,991 admissions in 2013 for marijuana/hashish
as the primary substance, 24.3% used marijuana/hashish daily. Among admissions to
treatment for marijuana/hashish as the primary substance in 2013, 27.4% were ages 12 to
17 years and 29.7% were ages 20 to 24 years.
Petitioners’ major comment in relation to Factor 7 and the Government’s response
1) The petitioners stated, “There is no severe physical withdrawal syndrome
associated with cannabis. Cannabis addiction is amenable to treatment.”
(Exhibit B, page 10). The petitioners further indicated that marijuana “may be
psychologically addictive, but much less so than other Scheduled [sic] II drugs,”
(Exhibit B, page 10) and that there is a low risk of dependence associated with
marijuana use. Petitioners further stated in Exhibit B, page 23, “Cannabis has
low relative dependence risk and does not reach the severity associated with other
drugs.”
The HHS states that marijuana withdrawal syndrome “appears to be mild compared to
classical alcohol and barbiturate withdrawal syndromes” and is similar in magnitude and
time course to tobacco withdrawal syndrome.
DSM-5 now recognizes and describes a marijuana [cannabis] withdrawal syndrome. The
lifetime risk of dependence to marijuana is approximately 9% among heavy or long-term
users (Volkow et al., 2014). Marijuana results in tolerance and withdrawal as described
earlier in this Factor 7. The data from NSDUH indicate that there is constant desire for
marijuana as noted by the consistently high numbers of current daily users in adults and
adolescents. Marijuana use also persists despite problems associated with the drug.
Changes in IQ have been noted in adolescent-onset, chronic or dependent marijuana
users, in addition to withdrawal symptoms. However, marijuana use has not declined in
the time that usage of this drug has been monitored. Additionally, there has been an
increase in content of the primary psychoactive chemical, Δ9-THC, in marijuana samples
analyzed by the University of Mississippi’s Potency Monitoring Project, suggesting
preference for marijuana strains with higher levels of Δ9-THC.
FACTOR 8: WHETHER THE SUBSTANCE IS AN IMMEDIATE PRECURSOR
OF A SUBSTANCE ALREADY CONTROLLED UNDER THE CSA
Marijuana is not an immediate precursor of another controlled substance.
DETERMINATION
165

 After consideration of the eight factors discussed above and of the HHS’s
Recommendation, the DEA finds that marijuana meets the three criteria for placing a
substance in schedule I of the CSA under 21 U.S.C. 812(b)(1):

1. Marijuana has a high potential for abuse.
The HHS concluded that marijuana has a high potential for abuse based on a large
number of people regularly using marijuana, its widespread use, and the vast
amount of marijuana that is available through illicit channels.
Marijuana is the most abused and trafficked illicit substance in the United States.
Approximately 22.2 million individuals in the United States (8.4% of the United
States population) were past month users of marijuana according to the 2014
NSDUH survey. A 2015 national survey (Monitoring the Future) that tracks drug
use trends among high school students showed that by 12th grade, 21.3% of
students reported using marijuana in the past month, and 6.0% reported having
used it daily in the past month. In 2011, SAMHSA’s Drug Abuse Warning
Network (DAWN) reported that marijuana was mentioned in 36.4% of illicit
drug-related emergency department (ED) visits, corresponding to 455,668 out of
approximately 1.25 million visits. The Treatment Episode Data Set (TEDS)
showed that 16.8% of non-private substance-abuse treatment facility admissions
in 2013 were for marijuana as the primary drug.
Marijuana has dose-dependent reinforcing effects that encourage its abuse. Both
clinical and preclinical studies have demonstrated that marijuana and its principle
psychoactive constituent, Δ9-THC, possess the pharmacological attributes
associated with drugs of abuse. They function as discriminative stimuli and as
positive reinforcers to maintain drug use and drug-seeking behavior.
Additionally, use of marijuana can result in psychological dependence.
2. Marijuana has no currently accepted medical use in treatment in the
United States.
The HHS stated that the FDA has not approved an NDA for marijuana. The HHS
noted that there are opportunities for scientists to conduct clinical research with
marijuana and there are active INDs for marijuana, but marijuana does not have a
currently accepted medical use in the United States, nor does it have an accepted
medical use with severe restrictions.
FDA approval of an NDA is not the sole means through which a drug can be
determined to have a “currently accepted medical use” under the CSA. Applying
166

 the five-part test summarized below, a drug has a currently accepted medical use
if all of the following five elements have been satisfied. As detailed in the HHS
evaluation and as set forth below, none of these elements has been fulfilled for
marijuana:

i. The drug’s chemistry must be known and reproducible
Chemical constituents including Δ9-THC and other cannabinoids in
marijuana vary significantly in different marijuana strains. In addition, the
concentration of Δ9-THC and other cannabinoids may vary between
strains. Therefore the chemical composition among different marijuana
samples is not reproducible. Due to the variation of the chemical
composition in marijuana strains, it is not possible to derive a standardized
dose. The HHS does advise that if a specific Cannabis strain is cultivated
and processed under controlled conditions, the plant chemistry may be
consistent enough to derive standardized doses.
ii.

There must be adequate safety studies
There are not adequate safety studies on marijuana for use in any specific,
recognized medical condition. The considerable variation in the chemistry
of marijuana results in differences in safety, biological, pharmacological,
and toxicological parameters amongst the various marijuana samples.

iii.

There must be adequate and well-controlled studies proving efficacy
There are no adequate and well-controlled studies that determine
marijuana’s efficacy. In an independent review performed by the FDA of
publicly available clinical studies on marijuana (FDA, 2015), FDA
concluded that these studies do not have enough information to “currently
prove efficacy of marijuana” for any therapeutic indication.

iv.

The drug must be accepted by qualified experts
At this time, there is no consensus of opinion among experts concerning
the medical utility of marijuana for use in treating specific recognized
disorders.

v. The scientific evidence must be widely available
The currently available data and information on marijuana is not sufficient
to address the chemistry, pharmacology, toxicology, and effectiveness.
The scientific evidence regarding marijuana’s chemistry with regard to a
167

 specific cannabis strain that could be formulated into standardized and
reproducible doses is not currently available.
3. There is a lack of accepted safety for use of marijuana under medical
supervision.
Currently, there are no FDA-approved marijuana products. The HHS also
concluded that marijuana does not have a currently accepted medical use in
treatment in the United States or a currently accepted medical use with severe
restrictions. According to the HHS, the FDA is unable to conclude that marijuana
has an acceptable level of safety in relation to its effectiveness in treating a
specific and recognized disorder due to lack of evidence with respect to a
consistent and reproducible dose that is contamination free. The HHS indicated
that marijuana research investigating potential medical use should include
information on the chemistry, manufacturing, and specifications of marijuana.
The HHS further indicated that a procedure for delivering a consistent dose of
marijuana should also be developed. Therefore, the HHS concluded that
marijuana does not have an acceptable level of safety for use under medical
supervision.
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